Anyone else having this problem? I have Avast Premier and I cannot, after the recent update, switch on my firewall. I just says I’m in danger because the firewall is switched off. When I try to switch it on it just says, “Cannot start firewall!”… What should I do?
My Windows Firewall is up and running, but Avast and WF has never had problems running at the same time.
It should be noted that under “Active protection” the firewall is switched off, but under “Tools” it is switched on.
Have you tried 2-3 reboots ?
Have you tried avast repair from ad/remove programs > …
For a Repair go to Control Panel/ Programs&Features/ Avast and click Uninstall/Change.
The Avast installation options screen will appear, scroll up/down and choose “REPAIR”.
Be sure to reboot after the process is complete
Yes as Pondus suggested a reboot or couple often resolves glitches in the Firewall status. 
It worked! Thank you 
Happened to me too after updating to AIS 11.1.2244 (Beta 3)… Reboot did not work, but Repair+Reboot fixed everything!
You’re welcome, glad it’s all squared away. 