Hi James, I don't know what is causing that.

Normally after an update is installed, the relevant files are cleared out and life continues as normal.

You could look in the following hidden folder and see whether you can learn more there:

C:\ProgramData\Mozilla\updates

Within the folder, there should be a subfolder named with a product identifier such as 308046B0AF4A39CB.

Then you should find an updates subfolder with logs and staged files for pending updates. (After an update, the 0 folder should be empty.)

In my last-update.log (plain text file you can view in Notepad) I have this for Firefox 68.0.1:

Performing a replace request PATCH DIRECTORY C:\ProgramData\Mozilla\updates\308046B0AF4A39CB\updates\0 INSTALLATION DIRECTORY C:\Program Files\Mozilla Firefox WORKING DIRECTORY C:\Program Files\Mozilla Firefox\updated Begin moving destDir (C:\Program Files\Mozilla Firefox) to tmpDir (C:\Program Files\Mozilla Firefox.bak) rename_file: proceeding to rename the directory Begin moving newDir (C:\Program Files\Mozilla Firefox.bak/updated) to destDir (C:\Program Files\Mozilla Firefox) rename_file: proceeding to rename the directory Now, remove the tmpDir ensure_remove: failed to remove file: C:\Program Files\Mozilla Firefox.bak/updater.exe, rv: -1, err: 13 ensure_remove_recursive: unable to remove directory: C:\Program Files\Mozilla Firefox.bak, rv: -1, err: 41 Removing tmpDir failed, err: -1 remove_recursive_on_reboot: file will be removed on OS reboot: C:\Program Files\Mozilla Firefox\tobedeleted\repfa795ad8-30c3-4378-bddd-6492df461ca7 succeeded calling QuitProgressUI

Not sure whether this is common or something new.

Hi... Many thanks for the quick response. When I look in the directory you suggest, there is just one file.... update-config.json. That file only contains the text "{"app.update.auto":true}"

Let’s do a full clean re-install;

Note: Firefox comes in three or more folders on all computers. They are;

Maintenance: (Programs Folder) <Windows Only> Firefox itself: (Programs Folder) And two folders in the profile of each user on the computer for each Firefox profile for that user.

If you remove the Firefox folder, the user profiles would not be affected.

Download Firefox For All languages And Systems {web link}

Save the file. Then Close Firefox.

Using your file browser, open the Programs Folder on your computer.

Windows: C:\Program Files C:\Program Files (x86) Note: Check Both Folders

Mac: Open the "Applications" folder. https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac

Linux: Check your user manual. If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it. See Install Firefox on Linux; https://support.mozilla.org/en-US/kb/install-firefox-linux

If you downloaded and installed the binary package from the Firefox download page, simply remove the folder Firefox in your home directory. http://www.mozilla.org/firefox#desktop ++++++++++++++++++++++++++++ Look for, and remove any Mozilla or Firefox program folders. Do not remove the Mozilla Thunderbird folder if there is one.

Do Not remove any profile folders.

After rebooting the computer, run a registry scanner if you have one. Then run the installer. +++++++++++++++++++++++++++ If there is a problem, start your Computer in safe mode and try again.

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode This shows how to Start all Computers in Safe Mode; Free Online Encyclopedia

Hello again. I've un-installed and re-installed several times already. I've tried the on-line and off-line installers. Both yield exactly the same results.

I've noticed that the uninstall is clean. The C:\Program Files\Mozilla Firefox directory gets completely removed. The C:\Program Files (x86)\Mozilla Firefox\plugins directory does not get removed, it contains one file.. npMeetingJoinPluginOC.dll. I believe this is a plug-in related to MS Lync/Skype for Business. However, the date on the directory is around the time the workstation was built, so I suspect its been put here by our standard build process. It certainly pre-dated any attempt to install Firefox. When Firefox is installed, there are no additional files or directories placed in the (x86) Firefox folder. Additionally, when Firefox is un-installed it seems to clean up the relevant registry keys under software in HKLM and CurrentUser. There's a couple of entries relating to un-installation.

What is happening for Firefox to decide that an update has occurred, is it looking for a file, directory or registry entry to change?

I'm a little limited to what I can do with this particular workstation as they are fairly locked down.

When you run Firefox, are you using Run as Administrator or just running with your standard user privileges?

Either way, it's a strange message for a new installation.

I've tried launching in both modes. Running as the standard user, and by running the Firefox executable as an Administrator. Both result in the same problem.

The only way I CAN get Firefox to launch, is by holding down shift as I click the Firefox icon (as a standard user) and running it in Safe mode.

It's a very strange message, especially as when I go into the Firefox options it clearly states that 68.0.1 is the latest version of the browser.

I've also verified the Mozilla Maintenance service is present in Services.

It could be the work of one of your add-ons, or it could be Hardware Acceleration. How to disable Hardware Acceleration {web link}

Type about:addons<enter> in the address bar to open your Add-ons Manager. Hot key; <Control> (Mac=<Command>) <Shift> A)

In the Add-ons Manager, on the left, select Extensions. Disable a few add-ons, then Restart Firefox.

Some added toolbar and anti-virus add-ons are known to cause Firefox issues. Disable All Of them.

If the problem continues, disable some more (restarting FF). Continue until the problem is gone. After, you know what group is causing the issue. Re-enable the last group ONE AT A TIME (restarting FF) until the problem returns.

Once you think you found the problem, disable that and re-enable all the others, then restart again. Let us know who the suspect is, detective.

I've been away this weekend, and won't be near my workstation again until tomorrow. I'm wondering if hardware acceleration could be involved. My workstation is a Dell Precision 7150. It contains 2 graphics cards, 1 is the onboard Intel Graphics, there is also an nVidia card. When I asked my colleague, who has the same laptop and Windows 10 build to try Firefox he experienced the same issue as me. However, when I asked two other colleagues who were using Dell and HP Ultrabook devices, Firefox installed without issue.

Graphics are relevant to how Firefox runs, but I don't know whether it would affect this issue. Since you had luck with Firefox's Safe Mode, you certainly could try disabling hardware acceleration. Fred's post had a link to the steps for that.

The only installed add-ons are: OpenH264, Widevine Content Decryption and Adobe Flash. The strange thing with Flash was that Firefox was complaining the installed version (25.0 r0) was out of date. So I updated it, but Firefox is not detecting it has been updated.

Disabling Firefox and/or Hardware acceleration didn't make any difference to the issue, it still persists.

Sorry should've put Disabling FLASH and/or Hardware acceleration didn't make any difference.