Since few days, once logged in elementary OS 0.4.1 Loki, when I have to enter my password (for exemple to update), I can't do it because the authentification box is kind of "shaking" with a high frequency and there's two different error messages displayed . The two error messages displayed (translated from french) are:
incorrect permissions on /usr/lib/policykit-1/polkit-agent-helper-1 (needs to be setuid root)
identification failed.Try again.
Thanks for your help.:)