If I have 2 or 3 sync errors does that just mean a couple files might not be recoverable if I lose a drive. Not sure how much time and money I want to invest in tracking down the issue. It is only tv and video files and i can replace on the server for the most part.

MOST of the time, it simply means the parity drive didn't get updated properly due to some "glitch" in the system.    UnRAID always assumes that, and simply corrects the parity when it finds sync errors.

 

Some like to do uncorrecting checks and do further analysis before correcting them .. I always simply do correcting checks; and if any sync errors are detected/corrected I then run another parity check to ensure it's okay the next time.

 

I've had very few sync errors in the 5 years or so I've used UnRAID => probably 3 different times it's had to correct some sync errors.  [it's been close to 2 years since I've seen one.]  Since I have a complete set of backups, every time there were corrected sync errors, I've painstakingly run a complete comparison of all my backup drives against the array, just to confirm there were no file errors => and those have always been perfect ... so I'm convinced that UNLESS some of your drives show errors in the drive error column the sync errors are indeed just glitches on the parity drive.