Thanks Jim, for pointing me in the right direction. The RoderickGI post that was linked to was especially helpful.
In a nutshell, here's what I did. All of my music files were on one drive.
1. Formatted an external hard drive to exFAT.
2. Used Copy and Paste to move all Folders from original drive to the external drive.
3. Made sure Library Backup was saved to external drive.
4. Detached external drive from Windows PC and attached it to Mac Mini.
5. Restored MC Library onto Mac Mini.
6. Used Rename, Move & Copy to to get the Library to point to the correct location.
Select Rename
Uncheck Directories, Filename boxes
Check Find and Replace
In my case, Windows drive was M:
When attached to Mac, I gave drive the volume name "MusicDrive"
Find what: M:
Replace with: \Volumes/MusicDrive/
I suggest starting with one or two files to make sure the change works and you can play the file. Once satisfied, you can select all and do the rest.