Sometimes it works. Most times it doesn't. Often MMW crashes during its background scanning, where I've been sending debug logs using the automated facility. I've turned it off for stability reasons. It scans for a while, with most results ending up "!", then crashes after scanning about 50 or more post startup.
Is it worth sharing a music vid that works, and one that doesn't? Happy to, but I can't spot much consistency as most of my MV files are encoded MP4 H264/AAC LC. Date ranges of the files that work are right up to present year plus ancient, and the latest stuff is definitely MP4 H264/AAC LC. Equally, there are 'modern' files that don't get analysed properly that I know are MP4 H264/AAC LC. I've no idea what's causing it to crash, but it doesn't do so when it isn't analysing to that's definitely the culprit.