When a user at our company tries to Synchronize all
folders in Outlook 2002 he gets this error message in 10
of 16 folders:

17:29:55 Error synchronizing folder
17:29:55                 [80004005-501-50A-550]
17:29:55                 The client operation failed.
17:29:55                 Microsoft Exchange Server
Information Store
17:29:55                 For more information on this
failure, click the URL below:
17:29:55                
< http://www.*-*-*.com/
us.asp?err=80004005-501-50a-550>

The link takes me to a troubleshooting paper on
synchronizing folders and I did everything that it
directed me to do. (delete the *.ost file, remove support
files and run repair, Etc.)

He still gets the same errors. He is running Win 2000 with
Office XP on the client and Exchange 5.5 with service pack
4 on a WinNT 4.0 server with service pack 6a.