When it says to restart to complete the installation, did you click the button that says 'restart' or just exit out of Firefox?

Certain Firefox problems can be solved by performing a Clean reinstall. This means you remove Firefox program files and then reinstall Firefox. Please follow these steps:

Note: You might want to print these steps or view them in another browser.

1. Download the latest Desktop version of Firefox from http://www.mozilla.org and save the setup file to your computer.
2. After the download finishes, close all Firefox windows (click Exit from the Firefox or File menu).
3. Delete the Firefox installation folder, which is located in one of these locations, by default:
   • Windows:
     • C:\Program Files\Mozilla Firefox
     • C:\Program Files (x86)\Mozilla Firefox
   • Mac: Delete Firefox from the Applications folder.
   • Linux: If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see Install Firefox on Linux. If you downloaded and installed the binary package from the Firefox download page, simply remove the folder firefox in your home directory.
4. Now, go ahead and reinstall Firefox:
   1. Double-click the downloaded installation file and go through the steps of the installation wizard.
   2. Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.

Please report back to see if this helped you!

I have hit both. It does not matter which one I hit. Every time I restart the computer it goes back to 20.0, and I am tired of it. I may have to switch to Chrome if something does not give soon. It seems that this point that I may have to format and start all over and that would be a pain in the rear!

Sometimes a problem with Firefox may be a result of malware installed on your computer, that you may not be aware of.

You can try these free programs to scan for malware, which work with your existing antivirus software:

• Microsoft Safety Scanner
• MalwareBytes' Anti-Malware
• TDSSKiller - AntiRootkit Utility

Microsoft Security Essentials is a good permanent antivirus for Windows 7/Vista/XP if you don't already have one.

Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Did this fix your problems? Please report back to us!

I have ran my anti virus, malware bytes and tdsskiller, as well as a couple of others, they all show no infectioin. I do not have Java on my computer, and nothing else is doing this. I have Opera and Chrome on my computer and don't use them much, but they have no problems. I am at a loss. I can not think of anything to do with this. I mean the last time I completely remove Firefox and installed 20.0.01 so there was no installation of 20.0 on the computer, nor were there 20.0 files on the computer for it to revert to. Yet it did. I hope that someone will have some idea how this could happen. It is a shame that you can't just ask Mozilla what is wrong. Argh!!!

As of Firefox 16.0 the updates are no longer shown in useragent so a chemspill update like 20.0.1 will show as 20.0 in useragent.

I am not talking useragent, I am talking about the version listed under the Help-About firefox listing. I am using Chrome for now, but I am keeping Firefox open to this thread in hopes that someone can tell me something to do to fix this. I will keep this thread open til the end of the week then uninstall if I can find no fix to this. I see this as a security risk.

Boot your Windows in Safemode and check out the Firefox issues is there or not

Which security software (firewall, anti-virus) do you have?

Try to boot the computer in Windows Safe mode with network support (press F8 on the boot screen) as a test to see if that helps.

Okay, I have commodo firewall, MS security essentials as my AV. Safe mode does nothing to stop Firefox from going back to 20.0 every time I restart the computer. I have to reinstall beta 21.0 every time I restart.

I can not find anything wrong. I have scanned the computer for root-kits, malware and everything. I have used 5 different scanners, nothing shows up.

I have just about given up on this!! It is just crazy.

How is beta 21.0 involved ?

Are you deliberately trying to install and run both the the Release channel (currently Firefox 20.0.1) and the Beta channel version Firefox 21 ?

If so you will have a custom install with two copies of Firefox installed, and you should have created separate Firefox profiles for each version.

See

• http://kb.mozillazine.org/Testing_pre-release_versions#Installing_multiple_versions
• http://kb.mozillazine.org/Using_multiple_profiles_-_Firefox

Firefox 21.0 Beta is what I put on after having so much trouble of 20.0. It updated to 20.0.1 or whatever it was called. It kept going back to 20.0 when I would shut down Firefox. Every time!!

At that point I completely uninstalled Firefox, taking Reg entries and all. I got rid of everything Firefox/Mozilla! Once it was all gone I installed 21.0 Beta in the hopes that it would fix it. It did fix the problem of reverting to 20.0 each time firefox was restarted. Now 20.0 comes back somehow after I restart the computer!!

I have scanned this computer 9 ways to Sunday to check for any nasties that might have gotten on it, however NOTHING shows up!

This is were beta comes from. This whole thing is driving me crazy.

I note the Comodo site http://antivirus.comodo.com/# talks about

• Comodo Antivirus Cleans Malware
• Defense+ Host Intrusion Protection
• Auto Sandbox Technology™

I have not looked any further but the above features sounds to me as if it includes a capability of preventing Firefox updating.

It is NOT comodo anti-virus it is comodo firewall and it has nothing to do with this. I am sorry, this is not a simple problem. I am not stupid! I don't mean to be harsh, but I think that the next time I will be posting will be from Chrome. I have had it!

Try to boot the computer in Windows Safe mode with network support (press F8 on the boot screen) and remove and reinstall Firefox this way.

You did make sure to remove the complete Firefox program folder?

• (32 bit Windows) C:\Program Files\Mozilla Firefox\
• (64 bit Windows) C:\Program Files (x86)\Mozilla Firefox\

Hello ozman812, try to Lock the preferences , and see if works

app.update.auto = false

app.update.channel = release or beta or nightly whatever you want to keep and install

app.update.url = to an empty string

app.update.enabled = false

thank you

Ok I have set things as you suggested. Now as I said above going into safe mode done nothing to prevent the reversion. That is the second time someone has suggested this, and it did not work, the first time as I made note of, nor did it work the second time. I am heading to bed now, but I will make note if this about:config thing worked to nor.

It will be interesting to see if locking the preferences work but Firefox is designed to UPgrade not to DOWNgrade so I would not expect it to be Firefox itself initiating the downwards change from fx 20.0.1 to fx 20.0.0

It appears to be something else on your computer that is causing this.

• Did you try cor-els suggestion of Windows safe mode (Run in Windows safemode, then restart in Windows safemode)

You may also like to try restarting the computer when it is not physically connected to the internet. If Firefox downgrades then it proves that the old copy of fx20.0.0 is somewhere on your computer still. (Could that be as some sort of backup)

Hi everyone,

I am still using Firefox, though I really had expected to move to chrome. I will say again, as I have at least 3 times before, safe mode did not do a thing.

I have a program called Revo uninstaller, which removes every trace of a program from your C drive. My back ups were on a external drive that I removed from my computer.

I took my computer off the internet, 20.0.0 still comes back. I have triple checked to make certain that it is NO where on my computer. Somehow, 20.0.0 is hiding somewhere or something is really screwed up. I will say once again that every scan for viruses, malware, Trojans and root kits, comes back negative.

This only happens now, as I have said before, when I restart the computer, not when I restart Firefox. I am at a loss, and I see nothing to do but to completely reinstall windows and I am not I'm the mood for that. I do not have 12 hours to do that. It takes at least that long to do all the re installs and updates.

I must admit I have no idea what is happening. I fail to see how this happens unless some third party application is unarchiving and reinstalling Firefox.

So you have uninstalled Firefox 20.0.0, checked the 20.0.0 file does not exist on your computer. You have checked that the working program path contains the Firefox 20.0.1

Then restarting in Windows safemode without internet access and Firefox 20.0.0 re appears and reinstalls.

Something is wrong. You are certain

• it is Firefox 20.0.1 that you have initially
• that the re-appearing version is 20.0.0
• you searched all connected drives for firefox.exe

I will have to leave this to see if someone else has ideas.