Question: Weird problems with High Sierra? Trusteer may be cause
On two iMacs I had very frustrating problems with a login sccreen loop. After installing 10.13 on the older (mid-2010) iMac and migrating to a new 2017 27" iMac, both would log in, run for about two mintues, then crash back to the login screen. Every time, unless booted in Safe Mode.
The older machine suggested a bunch of possible causes via Etre Check and Console. But the new iMac pointed right at the Trusteer rapportd process. (Note that there is a legit Apple rapportd process that has nothing to do with Trusteer and is not the issue here.)
Removing Trusteer from both machines fixed the problem. You will need the original Trusteer installer to uninstall.
Hope this helps somebody.
iMac, macOS High Sierra (10.13.3)