I would go into the update folder in LB and run the last version that was working. All you have to do is run that version from there and it will reinstall the previous beta you had working see if that helps then you can try updating again. This should only update the exe files and you are in no danger of losing any of your other files although all of that stuff should be backed up on another drive already so you don't have to do all of the work again if something goes wrong.