[RBraverman]

Well since the music library is populated from tags, there is no way for it to know what it hasn't got.

Compare files to what is IN the dB?

Video is different, based on parsing file names and fetching data online. Looking for "missing video" is just a matter of looking for unscraped files - those that you have not been able to lookup data for online.

I think what you want is a way to see what mess your tags produced...

Now, Now, there ......... it's just the classical stuff.

How I do it is a portable Kodi install, and just add a music source pointing only to those files I want to "test", and scan to library with "fetch online info on update" disabled so it does not scrape too. Then I ensure "show song and album artists" is enabled, and have a good look at the resulting nodes - artists, albums, genres and the relevant roles e.g composers, conductors, orchestras. Cock-ups, generally inconsistent spelling of artist names, are often obvious.

I'll give it a try. Not looking forward to it. The repair of my video dB cockup took 3-4 months. I could die still working on this one.

You could also have turned debug on before scanning, and have a look in the resulting debug log, but there are lots of false positive info in there at the moment e.g. tags found that Kodi does not process like ASIN or LANG etc.

The former seems easier and more efficacious.

Keep you posted.