Dear sir, We have a problem on Exchange 2007 Server. When user use OWA to access web mail calendar, server event log will show EXCDO error 8206: Calendaring agent failed with error code 0x8000ffff while saving appointment Type: Error Event ID: 8207 Category: General. Moreover server becomes working in very slow web mail response during any user click web mail calendar. Server performance return back after error message appeared in event log. It doesn't has problem if using Outlook to access mailbox calendar. Any suggestion to fix it ? Joe

Hello Joe, Error: 0x8000ffff (Error code 0x8000ffff) - As per some newsgroups postings, this error might be caused by an antivirus software interfering with Exchange Please letus know which antivirus software are you using . Also suggest you to refer this article if this apply to your case http://social.technet.microsoft.com/Forums/en-US/exchangesvrmigration/thread/8c254fb5-aee4-49a7-a564-3f3181902c5a/ If you need any additional information, please feel free to get back to us. We would be glad to assist you further.Viral R MCTS

Dear Viral, I am using Symantec mail security for exchange to the server. Regards, Joe Tam

Hello Joe , I mean File Level based antivirus software,make sure Exchange 2007 directories exclusions is set as per Microsoft recommendations Ref : http://technet.microsoft.com/en-us/library/bb332342.aspx http://social.technet.microsoft.com/Forums/en-US/exchange2010/thread/5a0101a0-76ff-413f-85c7-9074250234f1/ Also i would suggest you to temporary change the following Registry key and check EXCDO or DCOM errors when accessing the calendar. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\VirusScan\ BackgroundScanningIgnoreStamp to 0 then restart Microsoft Exchange Information Store. Note : The above registry will Disabled the File Level based antivirus software . Viral R MCTS

Dear Viral, The file level antivirus is Symantec client security version 10. I have tried to stop Symantec antivirus (File level) client service under control panel --> services, and also place all exchange folder in exclusion list. But problem still the same. As it is in production environment which cannot be restart information store. Do you think change registry will resolve issue even I stopped antivirus client ? Joe

Dear Viral, I have performed key updated : HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\VirusScan\ BackgroundScanningIgnoreStamp to 0 then restart Microsoft Exchange Information Store. After changed key value, no error occurs again in event log. As you mentioned that the key: backgroundscanningignorestamp is for file base antivirus only. Does it has any side effect for email scanning to keep in this setting ? As it seems that there are not obvious affect email attachment and spam scanning of operation this moment. Joe

Hi Joe, As I know, the default value of BackgroundScanningIgnoreStamp is 0: This setting has no effect. 1 : All items get scanned, even if their AV-stamps are up to date Frank Wang TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please 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.