Exchange: Outlook and OWA attachment issues

Outlook client does not display attachments

There are a number of reasons why this might be the case.

• See http://knicksmith.blogspot.com/2007/03/exchange-2007-and-outlook-2003-where.html. An issue was resolved by Microsoft in Exchange 2003 Service Pack 1 where Exchange 2007 was incorrectly causing Outlook 2003 to hide inline attachments. Even though you could not see the attachment, if you flagged the email, or clicked forward on the email, the attachment would appear correctly. Also if you selected Save attachments from the file menu, it would still save the attachments. OWA is not affected by this.
• See http://social.technet.microsoft.com/Forums/en-US/exchangesvrclients/thread/478c326b-486b-461c-9141-dd544b245c75. Symptoms: You can see the attachment in OWA but not in any of the current versions of Outlook. Outlook blocks the attachment completely and there is no way to retrieve it through this interface. This is also more likely to happen when an inhouse application has been programmed to send email with attachments. if the MIME is formatted incorrectly then Outlook will not display it. RFC 2387 describes the intended use of multipart/related:
  http://www.ietf.org/rfc/rfc2387.txt:
  "The Multipart/Related media type is intended for compound objects consisting of several inter-related body parts. For a Multipart/Related object, proper display cannot be achieved by individually displaying the constituent body parts."
  Steps to resolve this issue involve changing the MIME header to Multipart/Mixed instead of Multipart/Related. Multipart/Related will cause the attachment to be considered inline by Outlook. As there is no reference to the attachment in the body, it will then effectively be ignored. OWA has more smarts and is able to determine if an attachment is really inline or not. If it finds no reference to the attachment in the body of the email then it displays the attachment as a separate entity.

Exchange 20xx: Autodiscover and availability Issues

You receive the message: Allow this website to configure server settings?
You test e-mail autoconfiguration and it fails for no apparent reason.

The reason you receive the above error message is because the autodiscover website has been configured to redirect to a different website. For example, you might want to use https://webmail.domain.com/autodiscover/autodiscover.xml as your autodiscover URL. In this case you would redirect http://autodiscover.domain.com/ to that URL.

You may also receive this message if your autodiscover SSL website is not working correctly and fails. In this case, it will try http:// instead of https://. If you happen to have http:// redirected to https:// then you will also receive this message as this counts as a redirect.

You should be able to click the "Dont ask me about this website again" to make the message disappear for good.

Troubleshooting autodiscover messages:

• Use testexchangeconnectivity.com. It is there to help you find out if problems exist in Exchange client access from the Internet.
• If the user's primary email address is @domain1.com then is there an autodiscover record configured for this domain (either via an autodiscover website, redirection website, or a SRV record)
• Check the version of Outlook being used. If it is Outlook 2007 SP1 or RTM then the first thing to do is to update to Outlook 2007 SP2. This can fix a number of issues and also fixes an issue where the e-mail autoconfiguration autodiscover test errors out with 0x8004005 immediately after a line where it appears to succeed (returns a 500 response).
• Check whether the workstation is joined to the domain. This can determine the status of password storage and determine how you go about troubleshooting this issue.
• Check the user account credentials stored in the Windows profile. If credentials are stored for Exchange and yet the password has been updated since, you may get a series of password prompts and possibly autodiscover prompts appearing. In Windows XP you can access this by typing UserControl2 into the Start-->Run dialog box.

Using multiple email domains can affect autodiscover
Another issue that can occur with autodiscover is if your organisation uses different email domains. If autodiscover is configured on http://domain.com/ and the email address for the user is @anotherdomain.com then autodiscover will not be resolved. You might want to create SRV records for these domains to redirect users to the autodiscover website.

Authentication on web services and autodiscover virtual directories can affect autodiscover

Another issue that may occur if autodiscover is receiving errors (0x8004005) and Out of Office is returning an error "the server is unavailable". This may be because Windows Authentication may not be enabled on the web services:

get-webservicesvirtualdirectory | Set-WebServicesVirtualDirectory -WindowsAuthentication:$true

How Autodiscover works

A client attempts to connect to the SCP to get an autodiscover URL. If the client is not domain-connected then this will fail.

A client attempts to connect to domain.com and autodiscover.domain.com based on the user's primary SMTP address. It tries https first and then http.

See http://technet.microsoft.com/en-us/library/bb124251.aspx for a more detailed description.

Basic troubleshooting steps

When auto-discover stops working, you may find that your Out-Of-Office and Free/Busy (availability) stop working too.

Start the Outlook client. Hold CTRL and right click the OL icon in the system tray. Select Test Email Auto-configuration. Enter the email address and password. Select "Use Autodiscover" but deselect all the Guessmart checkboxes. Click Test. On the XML tab, ensure it is connecting to the correct autodiscover URL. You may receive one of the following errors as defined by Microsoft.

0x80072EE7 – ERROR_INTERNET_NAME_NOT_RESOLVED
This error is usually caused by a missing host record for the Autodiscover service in the Domain Naming service.

0X80072F17 – ERROR_INTERNET_SEC_CERT_ERRORS
This error is usually caused by an incorrect certificate configuration on the Exchange 2007 computer that has the Client Access server role installed.

0X80072EFD – ERROR_INTERNET_CANNOT_CONNECT
This error is usually caused by issues that are related to Domain Naming service.

0X800C820A – E_AC_NO_SUPPORTED_SCHEMES
This error is usually caused by incorrect security settings in Outlook 2007.

- If this is a workstation connected to the domain and able to reach Active Directory, ensure it gets a URL from the SCP in Active Directory and is able to connect to it. If it retrieves a URL but fails in using it, check that the URL can be accessed by pasting it into an Internet Explorer window. It may be that TMG or the proxy is blocking access to that server. The resolution in this case may be to add the URL to the proxy exceptions list.

- If this is a workstation that is not domain-connected, check that the correct URL is returned. If not, it has not been configured correctly as the external URL on the internet facing CAS server(s). If the URL is correct then try to paste the auto-discover URL into Internet Explorer and see if the autodiscover XML pops up.

- If you have an issue with seeing free/busy data for other users then try to enable logging in Outlook 2007 > Tools > Options > Other > Advanced Options > Select Enable logging (troubleshooting) > OK > Restart Outlook > Try to view free / busy information for another user > Go to the %temp% folder and open olkdisc.log file and locate the files in the olkas directory. These files can often provide information about which service is not functioning correctly.

- If you have an issue with seeing free/busy data for other users then review the event log for event id's: 4001, 4003, 4005, and 4011. Possible solutions for these errors are contained at http://technet.microsoft.com/en-us/library/bb397225(EXCHG.80).aspx

- Use the test-OutlookWebServices cmdlet to troubleshoot the availability service. For example, Test-OutlookWebServices -id:user1@mydomain.com -TargetAddress: user2@mydomain.com

- If you have an issue with seeing free/busy data for other users then check if there are any cross-forest timeout issues. Details are contained in the URL http://technet.microsoft.com/en-us/library/bb397225(EXCHG.80).aspx

- Check the SCP point in Active Directory Sites and Services by enabling the "View Services Node" option. It is under Services > Microsoft Exchange > Org Name > Administrative Groups > Admin Group Name > Servers > Server Name > Protocols > Autodiscover. These SCP points can be administered using the Set-ClientAccessServer cmdlet.

- If the issue is with external users, then use the website http://www.testexchangeconnectivity.com/ to check that your configuration is correct.

- If you have issues and you are using multiple SMTP namespaces then you will want to check out http://www.msexchange.org/articles_tutorials/exchange-server-2010/management-administration/exchange-autodiscover.html

- Check that IIS is started on all servers

- Check that the OWA application pool, OAB application pool, and EWS application pool are all running and started with no errors.

- If you receive an authentication error (such as 500 service not availabile or 400 login time-out) then you may need to rebuild the virtual directories.

Verify Configuration
Ensure you have configured the following: -
- Configure your internal URLs for all virtual directories. These should be automatically configured as the server name. Configure external URLS only on your Internet facing CAS servers. See http://technet.microsoft.com/en-us/library/bb691323(EXCHG.80).aspx for details on how to do this. The external URL will either be the name of a CAS server or an NLB that is sitting in front of a number of CAS servers.
- Configure certificates on each Exchange servers and TMG servers as required. These should be trusted by clients.
- Add all Exchange CAS servers to a proxy exceptions list - generally either using WPAD or Group Policy.

Outlook: Outlook Signature is corrupted

Symptoms:
Any text that is not bold would turn out bold when creating a new email, and visa versa.

The following steps did not resolve the issue:
Creating a new Outlook profile or creating a new signature.

Outlook can be configured to use Word as the text editor for new emails. This means that the normal.dot configuration will apply to these emails. If the signature is doing something funny when you go to create a new text file, it will most likely be an issue with this file.

Resolution:
Close all office programs. Rename normal.dot which for Outlook 2003/Windows XP is under the user profile under Application Settings\Microsoft\Templates. Start Outlook again and create a new email. The issue should now be resolved.

Note: This may cause a Word instance to appear in the background. Close Outlook, start Word, close Word, start Outlook. This has resolved this issue.

Outlook: Offline Folder (OST) issues

This article lists many of the ways in which you can troubleshoot an issue with the Outlook offline mail file. This file is often refered to as an OST.

Determine more about the issue:

• Record the error messages that are appearing.
• An error at the beginning that asks if you would like to start in online or offline mode indicates that Outlook believes there is a discrepancy between the information in the OST and the mailbox.
• Record the steps taken in order to receive the error condition. In some cases, the computer has to be shutdown, disconnected from the network and restarted before the OST issue will reveal itself.
• Have the user log onto another computer and perform the tests using the same version of Windows and Office if possible.
• Create a new test user with mailbox on the computer where the fault occurs, and see if the same issues occur.

Try the following steps to resolve an OST issue:

• Ensure the user has read/write access to the OST file location.
• Create a new profile and at the same time, change the location of the OST. If there is autoconfiguration involved, there may be a %username% in the location. Remove this and replace with a real path instead, as well as setting a name for the OST that does not already exist in that location. When it asks to create a new OST, click Yes. Finish the profile creation and set it to open when Outlook is next opened. The error message should generally be resolved by this step.
• Shutdown Outlook and rename the OST file. Restart Outlook and check if the issue reoccurs. Note: If the user has been writing to their OST and it has not been synchronised to the server, you will lose this information. Try to determine first if this is the case.
• Create a new Outlook profile.
• If the user is running Outlook 2003, you may try upgrading to Office 2007. This has been proven to resolve some OST issues (where the OST itself does not appear to be at fault).
• Try performing an uninstall and reinstall of Office. This has been proven to not resolve some OST issues.
• Empty out the deleted items folder. Deleted items may have become corrupted or too large.
• Remove any delegates on the mailbox. Delegates may have become corrupted and/or orphaned.
• Export any inbox rules and then delete what is there. Rules can become corrupted. These can be re-imported when testing is complete.
• Right click on a folder in Outlook and select properties. Select the synchronisation tab and check if the folder has synchronised successfully. If the synchronisation tab is not available then you may not be in cached mode. See KB842284. To synchronise all folders, press Send/Receive All. To synchronise just a single folder, select the folder and select Send/Receive this folder only.
• Replace the Exchange server service support files for Outlook. In Office 2007, rename the C:\Program Files\Microsoft Office\Office12\emsmdb32.dll. Go to Add/Remove Programs, select Reinstall or repair, then Reinstall. In Offce 2003 you should rename emsabp32.dll, emsmdb32.dll, emsui32.dll, then reinstall Office. See KB842284.
• Try running the OSTScan tool to check for corruption. Run without the automatic repair first. It will create a report in the deleted items folder. Check the report for issues. Rerun the tool in repair mode if required. See http://office.microsoft.com/en-us/outlook-help/scan-and-repair-corrupted-outlook-data-files-HA010075831.aspx?pid=CH100788841033#BM2
• Try moving the mailbox to a new Exchange server if this is an option.

Exchange: Outlook client and OWA issues and resolutions

General resolution steps

• Determine version and Service Pack of Outlook installed: http://support.microsoft.com/kb/928116
• Compact OST.
• Try moving the OST file (in the profile offline folder settings)
• Try creating new Outlook profile
• Try creating new Windows profile
• Try logging into the computer as yourself and creating a profile to see if the issue reoccurs
• Try doing Offie Diagnostics from Help menu
• Try doing a Repair
• Try Doing a Office Add/Remove Components and select a new component - this can sometimes do something that a repair does not.
• Download the freeware "OutlookTools" which shows information about your Outlook installation and allows you to empty Outlook temporary folders, run scanpst, scanost, set startup switches, configure Desktop Alert, modify list of blocked attachments and so forth.

Try uninstalling and reinstalling Outlook.

Problem: Client cannot send to a personal distribution list that is in their Outlook contacts and receives "an unexpected error has occured".

Resolutions:

1. Most commonly this is because the entry in the nickname cache has become corrupted. Simply delete the cached entry from the list when it appears.
2. Another reason might be that the personal distribution list has become corrupted. Try renaming the distribution list, which may resolve the issue. Also try recreating the distribution list.

Problem: Client is trying to book a meeting room and receives the error: "Resource declined your meeting because it is recurring. You must book each meeting separately with this resouce". You may not necessarily be booking a recurring meeting.

Resolutions:

1. Issue is most likely that the delegates have been corrupted on the resource mailbox. Open the resource mailbox in question. Remove the delegates and save the changes. Readd the delegates again with the required permissions. This should resolve the issue.
2. Check Rules and Alerts for any rules that may be forwarding meeting requests. This can cause an email to be returned to the sender that says the email was forwarded to such and such.
3. Is is potentially free/busy corruption of the resource mailbox calendar. This is a resolution provided by Microsoft PSS according to http://69.33.231.210/blog/2004/12/cannot-book-resource-outlook-thinks.html. PSS says this can occur if multiple people directly update a calendar at roughly the same time. This causes a number of attempts to simultaneously update the free/busy which then corrupts free/busy. PSS says users should not be directly updating calendars in resources, but through meeting requests. To resolve, change a resource scheduling parameter from Outlook. For instance, uncheck "Decline conflicting meeting requests". This generates fresh free/busy info for the resource. You can then go back and check it again - the free/busy info will get refreshed yet again.
4. Try regenerating free/busy data for the resource mailbox by creating an Outlook profile for it. Run Outlook /cleanfreebusy.
5. If you are running Outlook 2002 (XP) you should check out the article http://support.microsoft.com/kb/817420 to check whether a fix applies.
6. As per MS KB 312433, try adding the user back in as a delegate, and try to add the same permissions as they previously had. If the original delegate has been removed, try adding another user instead. Restart Outlook. Clear the "Send meeting requests and responses only to my delegates, not to me" Remove the delegate that you previously added. Restart Outlook. Send a meeting request and check if the problem is resolved.
7. See KB 252800 if Schedule+ 97 is installed.
8. If using Exchange 5.5, Exchange 2000, or Exchange 2003, follow the instructions as per MS KB 312433 to use mdbvu32.exe to remove the hidden delegate from the mailbox. Download mdbvu32.exe from http://www.microsoft.com/downloads/details.aspx?FamilyID=3d1c7482-4c6e-4ec5-983e-127100d71376&displaylang=en or http://www.chicagotech.net/exchange/exchange2007tools.htm.
9. If using Exchange 2007, use MFCMAPI instead which can be downloaded from http://mfcmapi.codeplex.com/releases/view/45245.
10. Download MFCMAPI. Create an online profile in Outlook. Open MFCMAPI and select the profile to use. Double click the mailbox name. In the left hand pane, expand root container then Top of Information Store. Right click the Inbox and select Display Rules Table... In the top pane, find the rule that contains "Schedule+ EMS Interface" in the PR_RULE_PROVIDER column, and double click it. In the bottom pane, right click PR_RULE_ACTIONS.... and select Edit Property. Copy and paste the contents to notepad and do a search for the ghost delegate. If the ghost delegate exists in here, delete the entire "Schedul+ EMS Interface" rule. This will disable all delegates and they will need to be readded to Outlook. If the ghost delegate is not here, search all other rules in the rules table for the name of the ghost delegate. In my case, I found a rule with the conspicuous name "which is a meeting invitation or update". When searching the PR_RULES_ACTION property for the ghost delegate, I was able to find it there. This is the rule that you should then consider deleting in order to resolve the issue.
11. Allen Song on an MS forum had this to say: To troubleshoot it, please first verify the non-existent user has been deleted completely by using ADSI Edit tool. If no clue in there, please turn to the delegate issue. Please understand that the delegate is represented by a rule that is hidden in the mailbox.
    The solution consists of two parts: Deletion of the delegate rules in the "Schedule" folder and secondly, removing the receive folder specification for the IPM.SCHEDULE.MEETING class.
    1, Remove the old delegate rules by:============a. Launch MFCMapi against the mailbox with an Online mode profileb. Choose Session -> Logon and Display Store tablec. Choose the Profile and choose OKd. Double click the mailbox storee. Expand Root Containerf. Right-click "Schedule" and choose "Open Associated Contents Table"g. Delete any messages in this table.
    2, Remove the ReceiveFolder Association by:============a. Launch MFCMapi against the mailbox with an Online mode profileb. Choose Session -> Logon and Display Store tablec. Choose the Profile and choose OKd. Double click the mailbox storee. Expand Root containerf. Ensure the Receive Folder association is set by going to MDB -> Display -> Receive Folder Table.f1. If the mapping is set, you should see one object in this list with the Message Class of IPM.SCHEDULE.MEETINGf2. Close the Receive Folder Tableg. Right-click "Schedule" and choose "Set Receive Folder"h. Enter "IPM.SCHEDULE.MEETING" in the box (without the quotes)i. Click "Delete Association"j. Click OK.k. Repeat step "f" above to ensure that the IPM.SCHEDULE.MEETING association is gone.
    After both of these steps, if you have set new delegate, you may still have to re-establish the new delegation one time to have it take effect.

Then in a separate posting, Allan Song wrote:

1. Please check whether the below thread can help you:http://social.technet.microsoft.com/forums/en-US/exchangesvrclients/thread/df98a5f6-74f6-4550-9e42-0b226f788199/Additionally, I would like to share the steps about how to delete Schedule+EMS Interface with you as below:
   1. Download MFCMAPI using the following link:http://www.microsoft.com/downloads/details.aspx?FamilyID=55fdffd7-1878-4637-9808-1e21abb3ae37&DisplayLang=en
   2. Launch MFCMAPI Editor3. From the Session Menu, choose Logon and dispaly store table4. Double click the mailbox (Mailbox-)5. Expand Root container, and Top of Information Store6. Right click the Inbox, and choose "Display Rules Table"7. This will open a new windows and will display the rules configured on this mailbox. The rules will be listed in the top half of this window. 8. In the top window of the Rules table, under "PR_Rule_Provider"column delete the entry with display name "Schedule+EMS Interface"10. Right click the Delegate Rule mentioned above ("Schedule+EMS Interface") and then chose Delete. This will delete the rule from the mailbox.

Problem: You receive the following error message:

---------------------------
Microsoft Office Outlook
---------------------------
Cannot start Microsoft Office Outlook. Cannot open the Outlook window. The set of folders cannot be opened. The file d:\data\outlook\misos\outlook1.ost cannot be accessed. You must connect to Microsoft Exchange at least once before you can use your offline folder file.

Problem: You receive messages when starting Outlook in cached mode that Outlook is entering recovery mode. If you press "continue" it will continue to open the mailbox but in Online mode, not cached mode.

Resolutions:

• Ensure "full" permissions are assigned to the user in question on the OST file and the folder containing it.
• If running Office 2003, upgrading to Office 2007 has been shown to resolve this issue.
• Exit Outlook and rename the OST file. Open Outlook and let it recreate the OST file.
• Move the OST to another location (Edit the Outlook profile and select "Offline folder settings" button to do this.
• Try recreating the Outlook profile
• Try recreating the Outlook profile and in the midst of creating the profile, check the path that the OST will be created at. If it contains a %username% or other variable in it, try replacing the path with one that contains no variables. Also make sure the destination has "full" access for the user.

Problem: Only a couple of recent emails, or no emails are appearing when in OWA. However all emails are appearing in the full Outlook client.

• Almost guaranteed this is because Outlook somewhere (or a mobile device) is configured to download new emails into a PST file rather than the Inbox on the server. So in actual fact there are no emails on the server to be seen.

Problem: Issues connecting to Outlook via a VPN connection:

• The firewall or network device on the home network may not be passing NetBIOS traffic. It is also possible to be a name resolution issue with DNS or WINS.

Problem: Unable to connect to OWA

OWA issues can be difficult to pick up sometimes. The errors however can give a clue as to the issues. Here are some common solutions to OWA issues:

• If OWA is coming up with authentication issues, ensure that ISA and Exchange are talking the correct authentication protocol. For example, if ISA is using FBA then ensure Exchange OWA / ECP virtual directories are set to Basic + Windows Integrated rather than FBA.
• If OWA is looping when trying to load the page (and sometimes also returns an authentication error message), this is a classic symptom of the webpage HTTP redirector being set incorrectly. Ensure the HTTP redirector is not trying to redirect back to itself. This is a common mistake that people make in their attempt to redirect HTTP to HTTPS on the IIS on the Client Access Server. Turn off the HTTP redirection and try again.
• If OWA complains about chain of certificates not being trusted, then you know most likely the ISA/TMG server does not trust the certificate that is on the Exchange server. If you browse to the Exchange website from the ISA/TMG server, it may appear to work (importing a certificate in one manner appears to make the error disappear in Internet Exporer, but does not mean ISA/TMG will trust the certificate) so do not use this as a reliable testing method. Go directly into the "Certificates" MMC console and check the Trusted Root Authorities for the certificate in question. If it is not a self-signed certificate, then also make sure all certificates in the chain are listed in the Trusted Root Authorities.

Problem: Outlook client returns error "Not specified" when trying to send/forward/create an email message.

Error message indicates a compatibility issue. In this case it may be that two versions of MS Word are installed, and Outlook is trying to use the wrong one. In this case it may not find the libraries that it needs. Try uninstalling the older version of Word and make sure it is the same version as Outlook that is left installed, if possible.

Problem: Outlook client returns error "Not implemented" when trying to send/forward/create an email message.

This may be that the installation has been corrupted or maybe some components missing? Maybe some prerequsites?

This has been resolved by repairing the product that is installed. Doing a complete uninstall and reinstall should also do the trick. Repair may not always work.

Problem: Outlook client returns error "an internal support function returned an error" when trying to send/forward/create an email message.

• Try reading http://support.microsoft.com/kb/222329 - this issue may be caused by a DL in the Outlook Address Book having the same name as a DL in the GAL. This would be resolved by renaming the DL in the OAB.
• Try reading http://support.microsoft.com/kb/259182 - this issue may occur if the user does not have read permissions on all OABs that are listed when you open the Global Address List and display address lists from the drop-down list.. This is resolved by either providing the permissions to the OAB in question or by removing the OAB from being displayed in the address book.

Problem: "MSVCR71.DLL was not found" error when starting Outlook 2007.

This issue occurs because the MSVCR71.dll and MSVCP71.DLL are missing from the computer.

• Copy these files across from a computer that is working. Preferably this computer would be running same version of Windows and Outlook. Restart Oulook. This time no error should appear on startup.

Note from http://msdn.microsoft.com/en-us/library/abx4dbyh(VS.71).aspx:

What is the difference between msvcrt.dll and msvcr71.dll?
The msvcrt.dll is now a "known DLL," meaning that it is a system component owned and built by Windows. It is intended for future use only by system-level components. An application should use and redistribute msvcr71.dll, and it should avoid placing a copy or using an existing copy of msvcr71.dll in the system directory. Instead, the application should keep a copy of msvcr71.dll in its application directory with the program executable. Any application built with Visual C++ .NET using the /MD switch will necessarily use msvcr71.dll.

Unable to find a mailbox in the address book or connect to a shared mailbox

• Check that the "Hidden from Address Book" is not checked on the mailbox
• If the mailbox has been created recently and is residing on Exchange 2003 or earlier, you will need to wait for the RUS to update the object, or manually kick off the RUS.
• If the mailbox is on Exchange 2007 and has been migrated recently, it may have not updated its status correctly. Make a slight change on the object, such as adding or removing a space from the Address and click Apply. This should cause the object to come back into the GAL.

Outlook blocked access to the following potentially unsafe attachments

This is due to certain attachment types being blocked in Outlook. Level 1 attachments are blocked and level 2 attachments require you to save to disk first. This "issue" can occur in Office 2000 SR1 or any later version of Office. The security was vamped up in Office 2003 SP3 and again in Office 2007. The reasoning given by Microsoft can be found at http://office.microsoft.com/en-us/outlook-help/blocked-attachments-in-outlook-HA001229952.aspx

Potential solutions:

• Use a file share to share files that may be considerec http://support.microsoft.com/kb/284414/
• Modify the registry or create a group policy using the Office ADM files to downgrade a level 1 attachment to level 2 so it can be saved to disk. See http://support.microsoft.com/kb/926512/ and http://support.microsoft.com/kb/829982
• If you are trying to open an Outlook message template (.OFT) then see the next section in this document.

Outlook blocked access to the following potentially unsafe attachments

The custom form could not be opened. An Outlook form will be used instead

• If you are trying to open an Outlook message template (.OFT) in Office 2007, you will find that you cannot open it directly. Even if you save to disk first, you cannot double click the OFT file and open it. There is currently no known workaround other than opening it using the following steps:
  
  1. Right click on the .OFT attachment and select "Save as..."
  2. Save to a location such as "Desktop"
  3. In Outlook, select the File menu --> New --> Choose Form...
  4. Select "User Templates in File System" from the drop-down list
  5. Click "Browse" and browse to the folder containing the new form and click OK. E.g. "Desktop"
  6. Select the Outlook template from the list that is displayed and click Open.
  
• If you are trying to open an Outlook message template (.OFT) in Office 2003 SP3, you will also find that you cannot open it directly. You can however revert the security settings to what was in Office 2003 SP2 and therefore allowing you to open the template file:
  
  Create the following keys in HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Options\Mail"
  AllowTNEFtoCreateProps"=dword:00000000"
  AllowMSGFilestoCreateProps"=dword:00000001

Meeting request shows "on behalf of" the message organizer

This occurs if a recipient of a meeting request then forwards the meeting request. This is considered normal behaviour. It is best practice to not forward meeting requests if you are not the meeting organizer. Replying to a meeting request does not show "on behalf of".

• http://msmvps.com/blogs/outlook/archive/2007/09/21/organizing-meetings.aspx
• http://support.microsoft.com/kb/899704

Logging in to OWA using the /exchange extension results in an error when accessing an Exchange 2007 mailbox.

You get this 500 - Internal Server error while you access Outlook Web Access from https://CASServer.domainname.com/exchange while https://CASServer.domainname.com/owa works fine.

This happens when you have seperate Exchange 2007 Mailbox and CAS servers. Ideally the request should be redirected to /owa but you get 500 - Internal Server Error right after typing in your credentials in the forms login page.

This happens due to the fact that redirection is not working because ISAPI Extensions are not installed on the Mailbox Server. ISAPI extensions handle specific incoming requests to the IIS server. Extensions are loaded when they are first needed and kept in memory until the host process shuts down.

To fix this issue, please install the ISAPI Extensions on the mailbox server. Here is the command that you have to run from the EMS to install them:

ServerManagerCmd -i Web-ISAPI-Ext

Make sure to do an IISRESET after this.

(from http://smarthost.blogspot.com/2008/07/500-internal-server-error-when-using.html)

This solution has been confirmed to be a solution.