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  1. I have rebooted. No luck.
  2. I have uninstalled Avast. Boot. Install again. No luck.
  3. I have uninstalled only the Firewall. Boot. Install again. No luck.
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Hi Lisandro. Is this on Windows 10? Will you please translate the image to English? I was curious as to what it says.

Is this close?
We recommend strongly restart your system. Some functions of the Firewall can only run after a restart.

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Repair Avast:

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