This is driving me nuts. I did a fresh install of Umbraco 8.15 and now I'm trying to connect to my 7.15.7 database to do the upgrade, except I can't login to authorize the upgrade! I can literally see that the passwords are exactly the same hash in both databases. I've tried logging in with the username and email address but neither work. And yes, membership providers are using legacyEncoding = true and all other settings match.

Does anyone have a clue? This has stopped my migration to v8 dead in the water and there's nothing I see that should be preventing a login.

Really need help, I'm sure someone else ran into this problem?