Cannot change any setting anymore

Avast Free Antivirus / Premium Security
1

Whenever I change the settings of any module in Avast Free Antivirus and press OK, it display the message “You are not allowed to perform this action. Please contact your system administrator”.
Before I was able to do everything and I didn’t change anything on my PC.
Avast 18.8.2356
Windows 8.1 Pro
Obviously I AM AN ADMINISTRATOR

2
  • Other security related software installed…?
  • Which AV(s) did you use before Avast…?
3

No other AV software. not related too…
I bought this PC 4 years ago and since then I had regularly Avast.
Never had problems until now…

4

Repair Avast:

  1. Control Panel → Add/Remove programs → Avast
  2. Click on ‘Repair’.
  3. Follow instructions.
  4. Reboot.
5

If Repair doesn’t fix the problem, try the following:
Clean Install of Avast:
https://goo.gl/4Ptzkf
If you need additional help with the Clean Install, watch this:
https://youtu.be/p-h3myRD51A