Yesterday, I got an update to 15.3--KDE environment...(yes, I haven't yet upgraded to 15.4)  Download went fine.  Install showed no problems.  Installed the update and I'm getting total system lockups, only resolution is the power button.  FWIW, my system does take snapshots as specified in the default installation.  I have no idea what is causing the problem.  Yesterday, just turning the computer on, and logging in would trigger a system freeze (power off required) today, I have been able so run some applications, but running Chrome causes a system freeze.
This is a stock system.  Anything I've added has come from the OPEN-SUES repos.
 
Is this a known issue?

If I should roll back to snapshot to before yesterday, should that restore things?  If that is what I should do, as I can't really count on getting info from the system, how do I do the rollback? (I've NEVER had to do one before)
 
Thank you a lot,
 
Mark