I have a similar problem.
I have always synced with Outlook, via Kies. I have Kies set up to automatically sync contacts and schedules whenever the gadget is connected. I do it for my phone (Galaxy S2) and my Tab 10.1.
Recently sync of schedule on my Tab 10.1 has failed at about the 98% point, with a caption "sync cancelled by user".
I do not experience the same problem with my phone. It processes normally.
Please don't suggest using Google! That is not my query, nor that of the OP!
If I wanted to use Google I would use Google!
What is the solution/fix for the reported problem?