As I said, Auto-Import shouldn't have been crashing. It would have been easier to fix the original problem than sort out what you have now, I suspect. There have been a few threads about Auto-Import crashing though, and if you find them you may get a hint as to why it is happening for you.
Anyway, when you say they are duplicates of the actual movies, are they pointing to the exact same file on disk? Because if they are, and you delete the bad records, then MC is going to think you have in the past deleted the good movie files, which could give you trouble in future. MC keeps track of what gets deleted, and won't allow it to be imported again, for instance. The fact that nothing appears beneath thumbnails says your problem isn't as simple as duplicate records, because a duplicate record should have the same movie name beneath it as the first record.
It could be a lot of work to sort out the problems in you current library.
Frankly, my approach to fixing this if it was my PC would be to;
1. Start with a new, clean MC library. Turn off Auto-Import when it starts its count down to start importing, which happens on first opening a new library. (Well, it may only happen with a new install. But don't let it happen anyway.)
2. Configure Auto-Import the way I wanted it via "Options>Library & Folders>Auto-Import>Configure auto-import" so that it doesn't run immediately after configuring. Add only a subset of folders to be imported, and check specifically the file types that would be imported for each folder being watched.
3. Turn on Logging for MC.
4. Run import for the current configuration. If there were any crashes, save the log and create a thread on the forum to get help with it, and ask if someone can look at the log.
You didn't say if you had an earlier version of MC before MC21. If you did, ad you still have the disk with it on, or backups, you might still have a recent backup of the MC library, which should be a better starting point than an empty library. But if MC21 is the first version that you have, or you have no library backup, then the method above should result in the underlying problem being fixed. That would be the best solution.
