I have been testing Unraid for a couple of weeks, and now I am on the Basic tier (different hardware and different USB sticks in both cases). During testing and now, with Basic, after a reboot, my initial root password is not accepted. I put 'root' as user and copy the password over from my pw-manager, which is not accepted. Then I have to go through the hassle of deleting 3 files on the stick and boot back up. Then I set the same password as new password, which works.
Next reboot, same scenario. Same, if I use a different password after deleting these files. This happens every time on reboot.