I was having same issue here (using windows 7 64-bit). iCloud control panel used to work fine for me before this last update, but then it stopped letting me sign in. After entering apple id and password, just hangs with the spinning progress wheel forever..
I tried uninstalling, rebooting, and then reinstalling the control panel, but still did the same thing. I also tried changing my iCloud password; new password worked fine for signing onto icloud.com and from my iPhone 4S but still not from the control panel. The strange part was let it would let me log into it with my wife's apple id ??
That got me experimenting some more and I realized that the control panel worked fine from a different user profile on my windows computer! After experimenting and nosing around in my profiles 'AppData' folder, I managed to get it to work again:
- If you have iCloud control panel log in window open, close it
- Copy this path to your clipboard:
C:\Users\%username%\AppData\Roaming\Apple Computer\Preferences
- Goto start -> run
- Paste the path and hit enter
- From the folder that is opened, rename 'MobileMeAccounts.plist' out of the way (or you can delete it if want..)
- Restart iCloud control panel and try logging on again. MobileMeAccounts.plist is regenerated the next time you sign out from control panel.
I'm guessing that somehow my (our) original MobileMeAccounts.plist has some sort of corruption in it, or maybe some log in attempt got hosed somehow and its preventing it from even trying? Who knows...
Hope it works out for you too!! ~~Corey