We're seeing users complain about an error message popping up on the computer screen. The error dialog doesn't contain much information about the program or the cause. Others receive an error "OutlookSyncClient has stopped working."

The Outlook Sync Client is used to sync iPhone, iPod and iTouch with Outlook. This error generally means there is a corrupt appointment or contact.

To fix it you need to find and delete the corrupt item. Most users found the easiest way to do this is to move or export the Calendar to a new PST file then delete the contents of the existing Calendar. Any appointment that won't delete is corrupt.

To fix, run scanpst on the data file then delete the corrupt appointment(s).

Create a new appointment and test the sync. If it works fine, import the calendar back into Outlook. If you are still getting errors (or have reason to believe its a corrupt Contact, move or export Contacts to a new pst and delete the Contacts from your mailbox.

How to Move the Appointments

1. Go to File (or Tools if using Outlook 2007), Account Settings.
2. Switch to the Data File tab and click Add to add a new data file to your profile.
3. Back in Outlook, go to the newly created pst file.
4. Right click on the pst name and choose New folder.
5. Type a name for the folder and choose Calendar type.
6. Go to your old calendar folder and apply a list view (such as All appointments in older versions)
7. Select All (Ctrl+A) and right click, choose Move to folder command to move them to the newly created calendar folder.

Any appointments that didn't move are corrupt.

Close Outlook, find scanpst (it's in the same folder as your Office applications, usually C:\Program Files\Microsoft Office\OfficeXX\scanpst.exe (where xx is your version of Office). Run it on the data file.

The scanpst wizard should lead you through the steps to fix the pst, but if you need instructions, see How to use Scanpst.exe to repair Outlook data files

After scanpst finishes, open Outlook and delete the corrupt appointments. Create a new appointment and see if it sync without error. If so, move the appointments back to the default calendar  and close the newly created pst file.