Hot on the heels of releasing OS X 10.8.4 Mountain Lion, Apple has gone ahead and released additional maintenance updates to iTunes. Update includes bug fixes for improved syncing and eliminated a sign-in bug some users were experiencing.
The syncing fix remedied an issue that some users were experiencing when switching between wireless and wired syncing. The new version is available in the Mac App Store's update section. Direct link for iTunes update for Windows PC and also for OS X.
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