Hello all, I am new to using the TechNet forums, so if I have posted this in the wrong place, I apologize. I have a single Exchange 2010 server, I can't remember what the last rollup/sp I installed on it was, but the build is 639.21 if that helps. It runs on 2008 R2 and runs all roles except UM. There is no other software on this server aside from backup software and MAPI/CDO. This server was installed and migrated from Exchange 2003 in early December. I followed all relevant documentation during migration and successfully moved all data to 2010 and removed 2003 correctly. I have not yet configured archiving, nor have I implemented replication of the databases. The majority of clients connect using Outlook 2003, 2010 is on the way, pending budget approvals for the fiscal year. A few have 2010 already. I have a user who connects to their own mailbox and an additional service-type mailbox using 2003. When the user tries to modify or delete certain contacts (only two that we have found so far) from the service mailbox, she receives an error about permissions and the contact is not changed/deleted. She has full access permissions to the mailbox and can change/delete other contacts in the mailbox. When I connect to the same mailbox using 2010 I can delete the contacts, but I receive sync errors and the following Error Event comes up in the Application Log on the Exchange server: Source: MSExchangeIS Mailbox Store Event ID: 1243 Error encountered attempting to update a categorized view to reflect an operation on a message. Database: Mailbox Database 1423960905 Folder: [MBX:mailboxname ][Restriction] MsgHeader ID: 1-101B097 Folder ID: 2-3E05C Categorization ID: 2-62686 Document ID: 116205 Message Operation: 2 Function: EcPreProcessCategMessageEvent Error Code: 0xfffff9bf If the original user accesses the service mailbox again through Outlook, the troublesome contacts are back and show up when I access OWA and when I access the mailbox from my Outlook. I haven't been able to find anything about this anywhere. The only reference I have found to event 1243 is an IP clustering issue, which does not apply here. I know this probably long-winded and not very well described, but I would happy to supply additional info and grateful for any help. Thanks

Hi, Can you post the detail permission error and the sync errors here for research? Have you accessed the service mailbox via some mobile device? At this stage, I suggest you temporarily turn off firewall and antivirus program, and then try to delete the contacts via Outlook 2010 again. If the issue persists, please capture the error message and upload it. Regards, NovakPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.