Avast blocks Firefox

[rapha.el]

I've just installed Avast 23.7.6074 (build 23.7.8348.762) on my Windows computer. Although I have made Mozilla Firefox an exception in Avast, and have unblocked Firefox in Avast, Avast won't let Firefox run. When I try to run Firefox, all that happens is that a small window appears stating -- "Firefox is already running, but is not responding. The old Firefox process must be closed to open a new window." -- and that window offers to close Firefox. However, other than that small window, Firefox is NOT running. And that small window won't "close" Firefox -- I must do that via ending the Firefox process in Windows Task Manager.

Can anyone advise how I can get Avast to allow Firefox to run? Thanks!

[DavidR]

Well Firefox is my default browser and I using it now without issue after updating Avast (details in my signature below posts) and no problem.

Have you restarted your system since updating Avast ?

What version of Firefox are you using  (details in my signature and images below posts) ?

[rapha.el]

DavidR, thanks for your reply. Yes, in trying to solve this problem, I have restarted the system -- quite a few times!

I am using Firefox 115.0.3 -- the extended support version for Windows 8.1. (I need to keep Windows 8.1 for a while longer, as part of a transition between computers.) I have also tried disabling all of Avast's shields -- without any effect on the Firefox blocking problem.

Since starting this thread, I have also discovered that Avast is not letting Google Chrome run either. I'd like to get both Firefox and Chrome running.

[rapha.el]

And now I've discovered that Avast won't let Mozilla Thunderbird run either!

[DavidR]

Thunderbird is also my default email client and no problem with that.

There is however an update waiting, which I haven't run yet, see attached.

[DavidR]

OK, just Updated Thunderbird and it is still opening and working fine

[rapha.el]

If one Googles "Avast read only" there are quite a few hits. I'm working my way through the suggestions in those discussions.

[Nom]

Why did you decide that the problem is in avast? Try enabling avast in passive mode.
It is also advisable to scan the system with an avast boot scan. And check the hard drive for file system errors.

[Nom]

If the problem is with avast, you probably shouldn't install the latest version in windows 8.1 It is better to install for example 21.2 and disable module updates.

[rapha.el]

Nom, thanks for the suggestions. I have completely uninstalled Avast. However, the Read-only problem that it made remains. I cannot undo that problem -- not even with the attrib -r /s command. Avast seems to have permanently altered the computer.

[Nom]

Maybe a system rollback?

[MrDJ]

this happened to me last time firefox auto updated to 115.0.2. small box in top left of screen. it wouldnt let me open full screen or drag to enlarge.
cleanup of cookies temp files and reboot solved issue without touching anything in avast and after that has opened as normal ever since.

[rapha.el]

Nom and MrDJ, thanks for the thoughts. A system rollback is certainly the right idea, but, unfortunately, that feature stopped working on that computer some time ago. As to the Firefox update, yes, that's always a possibility. However, the problem appears to have arisen immediately upon the installation of Avast. Another idea which I might try is to use the Avast Uninstall Tool. I uninstalled Avast via Windows, and I understand that leaves residual Avast files that can only be removed by the Avast Uninstall Tool.