Hi lee37, do you use Avast by any chance? Several Avast users are reporting similar problems today, as well as some that might or might not run Avast.

One possible workaround is to move Firefox to a different folder. This may help, but unfortunately I cannot tell you what is going on on your system.

Other Threads

• https://support.mozilla.org/questions/1290476
• https://support.mozilla.org/questions/1290490
• https://support.mozilla.org/questions/1290528 *
• https://support.mozilla.org/questions/1290513
• https://support.mozilla.org/questions/1290534
• https://support.mozilla.org/questions/1290540
• https://support.mozilla.org/questions/1290541
• https://support.mozilla.org/questions/1290493

Program Move Workaround

The user in that third thread reported that moving the contents of:

C:\Program Files\Mozilla Firefox

to

C:\Program Files (x86)\Mozilla Firefox

allowed Firefox to run. The user in the second thread reported that worked for them. I don't know why that would make a difference.

Thanks, but I'm not comfortable doing something like that on the computer.

I'll probably just have to find another browser and leave Firefox. Mozilla doesn't provide read this DIY community page and provides no technical support for its customers. If Mozilla does come out with a patch in a future update it will be useless to those who need it because those people can't open Firefox in the first place in order to receive the update.

I'll leave it on my computer for a month and will check back. If the issue isn't resolved by then I'll free up the space on the hard drive by removing Firefox.

Again, thank you jscher2000 for responding.

I think this problem might be caused by a program called Avast Cleanup, but we haven't had enough responses yet to track it down.

Here's another workaround suggested by a user in a different thread if you want to try it:

(1) Open the C:\Program Files\Mozilla Firefox folder

You can paste

C:\Program Files\Mozilla Firefox

in the Windows system search box and press Enter to load it.

(2) Scroll down to the firefox.exe file in that folder

(3) Right-click the file and choose Copy

(4) Right-click a blank area of the folder and choose Paste

Windows should create a file named firefox - Copy.exe

When you double-click firefox - Copy.exe does Firefox run normally?

Thanks, that copy/paste procedure allows Firefox to be opnned manually. Windows doesn't fully recognize Firefox as the default browser. When Firefox is launched a popup asks if I want to make Firefox the default browser. When I try to launch Firefox from VPN nothing happens. So I made a shortcut for firefox-Copy.exe. Untill, and if, Firefox discovers there's a problem and comes up with a fix in a new update I'll wait for about a month. I do appreciate the help.

Some problems occur when your Internet security program was set to trust the previous version of Firefox, but no longer recognizes your updated version as trusted. Now how to fix the problem: To allow Firefox to connect to the Internet again;

Make sure your Internet security software is up-to-date (i.e. you are running the latest version). Remove Firefox from your program's list of trusted or recognized programs. For detailed instructions, see {web link}

https://support.mozilla.org/en-US/kb/configure-firewalls-so-firefox-can-access-internet

In case you run Avast Cleanup, there is an update available that fixes this problem: https://forum.avast.com/index.php?topic=234798.0

I don't have Avast. After numorous manual sign-ins the sign-in issue seemed to have resolved itself.

Hi lee37, sounds like your issue is resolved, but we don't know the original cause.

Do you use AVG PC Tuneup, Speedup features, to modify programs running in the background? That is similar to the Avast Cleanup issue (Avast and AVG share a lot of code).

Yes, AVG PC Tuneup and it's speedup features which put programs to sleep when not being used.

Their Tuesday update seems to have put some of them into a coma. But they'll probably issue a cleanup update soon, so you can try the regular firefox.exe after that and it should work again.