Ron,
I’ve been getting the same thing periodically as well. Only solution is to uninstall & reinstall.
I run just the admin account, with firefly installed for that user only. My music folder is installed on a second internal HD.
I haven’t messed with permissions:
owner is andyg – access is read & write
group is andyg – access read only
others – read only
This has happened across the builds, I’m currently on the most recent of the nightlies.
Andy