Previously I'd just edited the basic info by right clicking the mp3 in the windows folder, selecting properties and then editing the details in there, they definitely all had the year, title and artist data correctly inputted. Now I'm actually having MM remove data from files, so now I've got over 100 that have no date, no artist, etc.

Two things seems to be occurring with MM, firstly it's obviously remembering some of the data from the files themselves from somewhere, as even if I clear both ID3v1 & v2 in the advanced tag options on MM, when I then go back to edit the file and put some of the correct data back it suddenly fills everything in again, even the zzzz fake album name I gave it ealier. So can I check to see where MM is getting this other info from or stop it making changes unless I tell it to?

Secondly, sometimes it seems to not be seeing the data that I have on the file already and creating blanks where there were none, same thing, can I stop it doing this? I have now unchecked the infer properties option and yet when I delete things in the album section, it still puts them back when I open it back up again, where is it storing and seeing this data from and why does it keep insisting I have data I repeatedly tell it to delete?

I suppose I don't want MM to try and be clever and do anything I've not told it to.

In that case your files may have been missing the tags in the first place which is why MediaMonkey inferred them from the filenames. As this can lead to unexpected results (after all it's guessing) you can use Tools > Auto-Tag from Filename to manually tell MediaMonkey how to interpret folder/filenames. Use with care and verify results before applying.

Thanks, but now it's gotten worse, now I've got a whole bunch of files that have just appeared in the MM library with no artist, titles or date, which they all had before??? Now if I click on those same files in my music folder they are no longer showing the details there either....

This all seemed to be working so well, I was working my way through adding in albums and art (the only details I was missing - I already had the correct titles and dates), I got to L, noticed the inability to delete album fields and leave blank and now I've spent 4 hours trying to put back in data that MM is seemingly rendomly deleting from my tracks each time I log back on.

2 steps forward 4 back each time....

Tools/Options - Library - When adding files to library - Untick Infer file properties.
That will stop MM trying to guess your tags.

I'm finally sorting through my music collection using MM and am going through each song, deleting unwanted info, adding in album art, etc.

The odd thing is if I close it off and then re-load I'm noticing certain tracks have random track numbers assigned, or something in the album section, where previously I have deleted everything. For example Janet Jackson - Doesn't Really Matter, I have now deleted 4 times the same thing that appears in the album section (it insists on saying 'CD Single'). If I actually look at the file using Windows there is nothing in the album section, I only see it on MM.

Any ideas?