MacOS – Unable to enter safe mode. Gets stuck at progress bar (100%) while trying to log in

macbook promacossafe-mode

Macbook Pro Retina 13", late 2013.

Unable to enter safe mode (via holding shift key). Result as in title.
Hangs after me waiting for mutliple minutes.

What troubleshooting can I do?

Need safe mode to do other troubleshootings.

Edit1: note, that the progress bar at first moves but very very slowly, compared to non-safe-mode logging-in.
Maybe I should wait overnight or something?
Is there a way to show any debug messages while this is running?

Also asked on Apple forum: https://discussions.apple.com/message/31699416#31699416

Best Answer

The "solution" was just to wait much much longer (longer than any other boot you have seen), patiently and not assume it was broken :).