If someone told you to re-sync your profile, we're guessing you are having a progress data issue with one of our Xbox games.
Before you re-sync, try restarting your Xbox and ensure that you are connected to Xbox LIVE. Hopefully, this easier, quicker solution will fix whatever problem you're having.
If that still doesn't work, it's time to try a profile re-sync.
**DISCLAIMER: ALTHOUGH IT IS A VERY SMALL RISK, there is always a possibility of data loss when deleting and re-downloading a profile from Xbox LIVE. DO NOT attempt a re-sync if you are uncomfortable with this risk.**
Xbox Support has written a great article that will help you re-sync.
Just follow these directions:
Best of luck, and we hope this helps!