This seems to result from deprecated MobileMe and iDisk preference files laying around. This post at the Apple discussion forum may help you delete the relevant files:

https://discussions.apple.com/message/19122650#19122650

This seems to result from deprecated MobileMe and iDisk preference files laying around. [This post][1] at the Apple discussion forum may help you delete the relevant files:

~/Library/Preferences/ByHost/com.apple.DotMacSync*.plist.lockfile
~/Library/Preferences/ByHost/com.apple.idisk*.plist
~/Library/Preferences/ByHost/com.apple.idisk*.plist.lockfile
~/Library/Preferences/MobileMeAccounts.plist
~/Library/Preferences/MobileMeAccounts.plist.lockfile
~/Library/Prefernces/ByHost/com.apple.coreservices.appleidauthenticationinfo*.plist
~/Library/Prefernces/ByHost/com.apple.coreservices.appleidauthenticationinfo*.plist.lockfile

Don't forget to close relevant applications (like Mail or Messages) before the deletion; it also might be a good idea to at least log out and in again afterwards. [1]: https://discussions.apple.com/message/19122650#19122650