You probably want to read the article on the Rename, Move, and Copy Files tool. It's rather long, but it's worth at *least* getting an overview of the tool before you start. I recommend this because, even though I'm going to give you some outline instructions, it's nice to know about this powerful tool before you do something important.
The outline is something like:
1. Make and MC database backup with File > Library > Back up library. Make note of where this backup file goes.
2. Turn off auto import in MC: Tools > Options > Library & Folders > run auto import in background > UNCHECKED
3. Now rename the subdirectory on disk. You'll probably use Apple's Finder to do this. Make note of the new name including capitalization if you have any.
4. Now the directory is renamed and MC will think that all of your files are gone because you changed their location. All of the "pointers" to the files that are in MC's database need to be updated. Luckily this is easy to fix.
5. Use the RM&C tool.
A. Select all of your files in MC that were in the old directory you renamed.
B. Open RM&C: <right click> > Library tools > Rename Move and Copy Files
C. Choose your mode: Update Database to point to new location. <----- IMPORTANT
D. uncheck everything
E. Check only "Find & Replace"
F. In the "Find What" box, put the name of your original folder, the one you just renamed. If it was "Music" put that here.
G. In the "Replace With" box, put the name of the new directory.
H. VERY IMPORTANT: Look over to the right in the preview pane. Look at the paths that it's going to rename in the database. Make sure they look correct. If they are not correct, trying making changes to the Find or Replace text. Make 100% sure it's right before you continue.
I. Press OK, and it will update the database records for all files you have selected.
It might be smart for you to do start at 5A and only select one album as a test. Go all the way through and then make sure that album works from MC again. Once that works, return to 5A and select all the rest of the files. Or another big chunk.
What if you get through all of this and it's all totally screwed up in MC and you can't fix it? Remember that database backup we made? Just restore the database backup and it will all be back to normal. Minus whatever you have done on disk outside of MC.
This is easier than it seems from reading all of my steps. RM&C is a great tool that lets you do cool stuff like this. I've used it dozens and dozens of times. It's your new friend.
Good luck.
Brian.
