Outlook 2003 users receive the error message "Unknown error" while doing things like deleting emails.

Outlook 2003 users receive the error message "Unknown error" while doing things like deleting emails.

The users simply click OK and the error goes away. Then when they try to do what they were originally trying to do (such as deleting an email) they are usually able to do so without any problems.

This has started happening after the company's Exchange server has been migrated from Exchange 2003 to Exchange 2010.

What do I need to do to fix this issue so that users will stop receiving this "Unknown error" message within Outlook 2003?

The user's client computers are Windows 7, Windows 7 64-bit, Windows Vista, and Windows XP SP2.

Please provide me with the exact steps.
IT GuyNetwork EngineerAsked:
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Any migration issues? I would first run the Exchange Best Practice Analyzer on the Exchange 2010 to see it there are any issues to fix.

What about a new client / test account same issue?

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Maen Abu-TabanjehNetwork Administrator, Network ConsultantCommented:
please check event viewer and tell the event ID and description raised.
Upgrade Exchange 2010 to SP2, which contains several Outlook 2003 UDP Notifications fixes
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IT GuyNetwork EngineerAuthor Commented:
I have done the above mentioned things and have even uninstalled and then reinstalled Office 2003 (including Outlook 2003) on the user's computer.

I have also installed all Windows and Office updates on the user's computer.

The user still intermittently gets this error.

Does anyone else know of what else I might be able to do to fix this issue?

The Windows event longs don't display anything unusual or out of the ordinary.
Maen Abu-TabanjehNetwork Administrator, Network ConsultantCommented:
can you post screenshot to this error??
Maen Abu-TabanjehNetwork Administrator, Network ConsultantCommented:
listen go to Exchange 2010 powershell and run this command :

Set-RpcClientAccess –Server –EncryptionRequired $false

-server is your server name ...
then close outlook and try agan
Did you upgrade to Exchange 2010 SP2? Another thing you can try is "Outlook /safe" on the user's machine.
if its only one user I would recreate the mailbox for that user Export the Mailbox to a PST File detach / remove the mailbox from that user recreate and attach and Import all settings

if everyone is experiencing this problem try Office 2007 and above

check this out
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