iPad video failing to appear after syncing

My iPad has about 20 full digital movies that played perfectly.Next time I synced my iPad by iTunes. I selected "Sync Movies" and "Automatically Include All Movies" on the Movies tab. But after syncing, the videos do not show up on my iPad.Doing the following steps to fix the issue* Open iTunes and uncheck sync music, movies, tv shows.* Remove all library files by clicking apply to sync.* Recheck