Most machine that are upgraded to Big Sur are running Song Surgeon correctly. However we have seen issues an a small percentage of machine where the app seems to hang. Here is what you need to do.
Please go to your Applications folder. Find the Song Surgeon icon, right click it and select "Move to Trash". This will uninstall Song Surgeon.
Next, download this new build using this link and install it.
http://songsurgeon.com/files/SongSurgeon5.dmg
After this, download this small script.
http://songsurgeon.com/files/Fixer-SS-BS.dmg
After downloading double click the .dmg file. This will open a small dialog window which will show a file inside of it with a graphic. Double click this graphic and it will run the script and return a message. Hopefully it will say "Everything is fixed".
If this doesn't fix your problem, please complete a Help Desk ticket.