Been struggling with this issue for days and I've had advice from other online forums, as well as the i-mate online assistance. The latter advised me to re-download and install WMDC6.1, which I did. I've also downloaded AS4.5 and re-installed that on the laptop.

Specifically, the error message is "Activesync encountered a problem on the desktop" on both machines.

I dock the i-mate with my work laptop using AS4.5 as well as my home pc using WMDC6.1.
When the problem occurs on the laptop, I can fix it by removing the content sync and then re-enabling them.
But when I connect to the desktop, I get the same problem and I can also fix that with the same method.
However, if I then connect to the laptop, the problem repeats!
Ad Infinitum!

When I remove the Sync Content on either machine to affect the repair, I lose all the data in the content folders, e.g. Contacts, Tasks, Calendar when I connect the phone. Which means I lose all my Speed Dials.

After enabling the Sync Content, the data is refreshed on the phone.

Prior to getting the i-mate, I was using a Dopod C730 and it worked seamlessly across both machines. That leads me to believe that the problem lies with Windows Mobile 6.1 Professional, which is what came with the i-mate. The Dopod was WM6 Standard.

Does anyone have a fix for this frustrating problem?

I might end up having to only sync with my work laptop, cos that's where I get my Calendar and Contacts primarily.