Was MediaMonkey allowed to modify the files? In MediaMonkey the option to do so needs to be enabled under Tools > Options > Tags & Playlists and in Windows Explorer you need the rights to modify the files.

You can try a force write of changes by selecting the files in MediaMonkey and using Tools > Advanced Tag Management > Synchronize Tags on the files you've changed and the values you see in MediaMonkey will be saved to the files.

thanks, I appreciate your help.
I made a bunch of changes to many of the tracks on media monkey, added a couple of new albums, and tinkered with a bunch of existing files.
I re-plugged the hard drive into sonos, and hit update the music library.
all the new tracks were now there. however, none of the changes I put on the other files were there.
I even removed the drive from the sonos music library, and then re-added it, but the changes to the existing files wasn't reflected.
Am i missing anything?
I appreciate your help

Yes, you can edit the files in MediaMonkey, it's up to Sonos to update its database after you've edited the files.

Dumb question.
I have a hard drive with about a thousand songs on it that I have for sonos playback.
However, some of the artist names are duplicative but a little bit different, some just need to be corrected.
but many have the album info and artwork etc. associated with the folders
Can I install media monkey on my laptop, plug the hard drive into it, and use media monkey to correct and clean up the songs?
Will it modify the format or anything, messing up my sonos library?
I know this is a pretty dumn question, but I appreciate you help.