The Amazon Music installer improperly sets the permissions for it's data directory on install.
The fix is simple, just change the ownership to the current user.
Steps:
- Install Amazon Music
- Open terminal (cmd-space, type in terminal)
- Copy and paste this command:
sudo chown -R $USER "~/Library/Application Support/Amazon Music"
It will prompt for your password and change the permissions on the Amazon Music data directory to be correct