HandBrake converts only those DVDs that can be played on the DVD player. So if you have a video file in formats like AVI, MPG, etc., then it won’t convert. If you want to convert your DVD video ...

HandBrake, the free and open-source video converter and encoder ... so you can export video files using HandBrake in the VP9 format without losing any video quality for the original source.

If it works fine, then set it to run as administrator always. The important files required for the HandBrake to run might be corrupted or missing. There might also be bugs from the previous update ...