The only thing that worked for me was to downgrade to :3.10.5 (after which I could login, but camera firmware not supported so they were disconnected). Then if I jumped up to 3.10.8 I could still log in, and the cameras would connect. Restoring/Analyzing the DB brought back all previous recordings.
I tried going from there up to 3.10.10 but had the login issues again, so back to 3.10.8 and it seems to be OK.