Server: Sharepoint 2010 Client: Outlook 2007 SP3 on XP SP3 When I try to use "Sync with Outlook" feature on a sharepoint calendar i get the following error in Outlook: Task 'SharePoint' reported error (0X8000FFFF) : 'An error occurred either in Outlook or Sharepoint. Contact the Sharepoint site adminstrator. HTTP 400' Here is the kicker, When I use Fiddler to monitor what is going on, the syncing process works great, when i disable fiddler, it breaks again with the above error. Guidance is greatly appreciated. Regards, Brian

Hi Bgullo, Thanks for posting in the MSDN Forum. I would recommend you post your issue in SharePoint forum for better support. Have a good day, TomTom Xu [MSFT] MSDN Community Support | Feedback to us

Thanks, Moved to http://social.technet.microsoft.com/Forums/en-AU/sharepoint2010general/thread/f5437f6b-5a8f-4a43-930f-8508f0f706b8 Brian