What operating system are you using? Windows 8?
What version of Android are you using on the GS3? Stock or custom ROM?
Are you using USB or AirSync? Did you get any errors during the sync?
Here is a step by step guide to syncing using doubleTwist 4.0 (available for Windows 7 or Windows 8 only) along with some troubleshoot tips.http://www.doubletwist.com/help/question/guide-to-syncing
If after trying the troubleshooting steps, you are still experiencing problems, please send us a debug package from your PC immediately after encountering the errors.
You can do this by holding down SHIFT while right-clicking on the doubleTwist icon in the System Tray and selecting "Send log files…".
Here's a short help page on how to send the debug package.http://www.doubletwist.com/help/question/doubletwist-sync-debug-mode/#E
Please include this G+ URL in the "Additional Information" section for reference.plus.google.com/u/0/107162430587058785967/posts/Si9cyjt6zQC?cfem=1