Not having a clue is not a bad thing... Harder to admit for me at least. As far as the problem I'm experiencing, I don't think it's windows 7 specific. It happened to me in Vista too both 64bit. The process is called AppleSyncNotifier.exe... a 32bitter.
It normally hits 50% when syncing my calendar, contacts, favorites, etc to the cloud when something is updated from the iPhone or the cloud, or from the computer. It then settles to 0% when done syncing. The sync is 100% dead on and always reliable, unless I kill the process - obviously

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But every now and then it sticks at 50%. Apple's latest update shows support for windows 7, hopefully giving me relief, but nothing.
ideas?