A suggested fix was posted:
https://forum.avast.com/index.php?topic=182468.msg1294333#msg1294333
Thank you. Unfortunately neither a 'repair' or 'clean install' worked and I still cannot temporarily disable Avast's Shields from the Avast icon in the Notification Area. Please advise.
Then you most likely have other issues and might need some help following the information outlined here:
https://forum.avast.com/index.php?topic=53253.0
Thank you. I'm very fortunate to have the ability to create VM's. So I created a new Windows 7 x32 VM with 4 GB ram and dual core CPU and installed Avast Free. No other software installed and the only Internet connection was to download the Avast installer. Tried to right-click and disable shields but to no effect. The
Action Center icon in the
Notification Area showed an exclamation mark in a yellow triangle so I opened it... to find 2 entries to "Turn on avast! Antivirus" and that Windows Defender had not been turned off.
Next, I loaded a bare (but activated) Windows 10 Pro x32 VM (again, 4 GB ram and dual core CPU) and, using a local account, installed Avast Free. Once again, no other software was installed and the only Internet connection was to download the Avast installer (using Edge) and install it. Tried to right-click and disable shields but to no effect.
I accept that my entire home network may possibly be compromised despite my best efforts (Avast, Malwarebytes) and 35+ years experience of building and fixing PCs, clearing malware, etc. (including many years as a Senior IT Officer then IT Manager for a local authority) .... but I think there's currently a problem with Avast.
Edit: More info. Amongst my downloads I found the installer for Avast Free v11.1.2245.1540. I reverted my W10 VM to its original snapshot (i.e. installed, activated and nothing else) and installed Avast Free. It informed me it was out-of-date but I didn't update. I still could not disable Avast's Shields using the right-click context menu of its icon in the Notification Area.
To double-check, I reverted the W10 VM to its original snapshot (i.e. installed from new, activated and nothing else) and re-installed Avast Free v11.1.2245.1540 a second time... and didn't update. I just waited until the 'You are protected/ Up-to-date' dialog appeared then closed the dialog.
Same thing... I still could not disable Avast's Shields using the right-click context menu of its icon in the Notification Area.
Sorry but, I stand by my original query... Is this a bug or a deliberate change?