Updated to 25.1 Free (25.1.9816a build 25.1.9816.762) today and Restarted.
Ran into a problem immediately. Windows Security icon showing Yellow and Avast icon showing redX.
“Web Shield is turned OFF”.
From UI invited to turn Web Shield ON. Lasted 1 second and then turned itself OFF again.
Repeated that cycle a few times with same result i.e. Web Shield cannot be turned ON.
Did a second Windows 10 Restart.
Same problem. Attempted to turn Web Shield ON via UI. Failed as before.
Decided to try RepairApp via UI>Menu>Settings>Troubleshooting.
After repair. Web Shield = OFF.
Tried again via UI to change Web Shield to ON. This time it appears to have stuck.
I will do another Restart.to check this is now working OK.
I hope noone else updating to 25.1 encounters this problem as it is not straightforward fix.