Removed 400 or so comments from tracks and lost file path

Did you change anything about the artist or album? That would have moved the file location if iTunes is set to manage your files.

@Pulse No just the comments tab. 

Do you have iTunes set to manage your tracks?

Yes I think that option is set although I've always been told this is the best way around? I can't find the menu now.

Good golly no, that's the worst thing you can do -- as you just noticed, iTunes will move files at its whim!

Look under the Advanced tab of the Settings:

Unfortunately you'll have to relocate the files manually, or if you use the iTunes sync, simply re-sync using the manager.

Hmmm My settings > Advanced Tab doesn't show that tick box?

Hrm, that was on the Mac, may be in a different place on PC? Are you running the latest version?

I'm on 3.2.0 on a Mac. 

I meant of iTunes... ;)

FYI - that Advanced tab I was referring to was within iTunes.

It's been a long day! I've un-ticked in iTunes now. Hopefully this will save me some trouble in the future!

Thanks 

Were you able to start relocating them within rekordbox or did you use the sync manager?

I re-located the tracks manually - I can't believe changing that tick box in iTunes has made my life so much easier!! I've easily amended thousands of files since. It was someone on the NI forums who told me to use it in reverse when I had a short term relationship with an S8.