Mojave: Macbook Pro (2011) loads endless after password so I try to fix this annoying problem of a pretty aged Macbook Pro (2011) with Mojave.

What I've done?
I created a TimeMachine Backup to move from the old HDD to a new SSD. The creation and importing of the TimeMachine worked like a charm and I can see the old user. Since there is currently no password for this user all I have to do is pressing enter to start to login. But here is the problem: The loading animation never ends and the login process runs endless. 

I've already tried to several things to fix this problem:
- Reinstall Mac OS
- CMD + OPTION + R + P to reset NVRAM and PRAM
- Let it stay untouched (more than 20 minutes) but no progress

Do you have any tips how to fix this?

Thanks in advance :)
Interesting... this is an issue when you haven't set a password. I set a password with a different admin user and now it works.