I guess that reproducing problem can be: install Enpass Extension for Firefox. Each time you will log-in to some web page, you will get Enpass Pop-Up windows for entering the pin. N-Logins = N-EnpassHelper.exe runnig and eating CPU till the full computer crash.
Same problem here. Enpass 5.6.5, Firefox 56, Chrome (latest); Windows 7 Enterprise x64, i7-4600, 16GB RAM. Fast fix awaiting. :-)
Just one user. Doing after fresh start as well as after from-hibernation wake-up.