I've run DISM and SFC to cleanup the windows image and file check. After running these both successfully, and reinstalling Firefox through the installer, the problem persists.

Manually copying and pasting "vcruntime140_1.dll" from another program into the "C:\Program Files\Mozilla Firefox" directory seemed to rectify the issue. However, this seems tenuous as a fix.

DLL was copied from "C:\Program Files\WindowsApps\Microsoft.VCLibs.140.00.UWPDesktop_14.0.27810.0_x64__8wekyb3d8bbwe"

It seems odd that it's looking for an _1 file. In the regular program folder

C:\Program Files\Mozilla Firefox

there should already be a

vcruntime140.dll

file for Firefox's use.

???

I suspect there is a flag somewhere to look for the other one, but off the top of my head, I don't know where that would be.

What if you try this in the Firefox program folder mentioned earlier:

• right-click vcruntime140.dll > Copy
• right-click a blank area of the folder > Paste
• find the copy (e.g., vcruntime140 - Copy.dll) and right-click > Rename it to vcruntime140_1.dll

Does that help?

Whoops, our replies crossed. Is the _1 file identical to the original one in the folder or is it a newer version?

Looks like they're significantly different; *140.dll is 86kb, *140_1.dll is 43kb. Like I said, I just searched my machine for a copy of that DLL and copied it over hoping it worked, and having used it all day, so far so good.

• 140.dll was automatically added during the installation, correctly.

I tried you above suggestion - for more data - and deleted *140_1.dll, then copied/renamed *140.dll as described above. This caused the same issue described, where tabs would fail to start loading. I didn't try a full uninstall/re-install. Suffice to say, 140_1.dll is required on my computer for Firefox to run.

See also:

• Bug 1624546 - Include vcruntime140_1.dll for VS2019 16.5 x64 from the redist directory in the package

(please do not comment in bug reports
https://bugzilla.mozilla.org/page.cgi?id=etiquette.html)

I was using Firefox 78.0.2 64 bits on Windows 10 and had the same problem today.

@trevorawestphal solution worked for me, thank you!

Cheers

This worked for me:

1. Uninstall Firefox.
2. Do this: https://knowledge.autodesk.com/support/autocad/troubleshooting/caas/sfdcarticles/sfdcarticles/Error-The-program-can-t-start-because-VCRUNTIME140-dll-is-missing-from-your-computer.html
3. Restart your PC.
4. Install the latest Firefox as a new install (When asked choose "new profile" or "fresh install" or whatever).

System: Win10 Home 64bit

Trying to resolve this problem for a friend. She had the same problem of Firefox not loading any websites so I tried refreshing and then reinstalling Firefox v80. I got this same error during installation "firefox.exe - System Error The code execution cannot proceed because VCRUNTIME140_1.dll was not found. Reinstalling the program may fix this problem."

The problem is this file does not exist on her system anywhere. Nobody as far as I know uninstalled any redistributables or runtimes - my friend never uninstalls anything.

So, for anyone who also does not have a spare copy of this file, you may need to find a friend with Windows 10 and copy the file from their system.

However, I searched my system and I have 3 copies of this file - in C:\Windows\system32, in C:\Program Files\WindowsApps\Microsoft.VCLibs.140.00.UWPDesktop_14.0.29016.0_x64__8wekyb3d8bbwe\ and in C:\Program Files\WindowsApps\Microsoft.VCLibs.140.00.UWPDesktop_14.0.27810.0_x64__8wekyb3d8bbwe\ so it's not exactly clear which one to use except I don't think the 32-bit one will help. I will try the others. (I can't do it yet but I'm posting this now while it's fresh in my mind but will update later if it works.) But if these files don't exist on someone's system, how would they fix their Firefox? This seems like a major flaw to have a dependency on a file that may not exist on the system. Copying the file from your own or another person's system is not really a solution - more of a workaround. (I note in the bug report they were considering packaging the file with Firefox but no movement seems to be taking place on that.)

So how does this situation come about? Her Firefox worked one day and then stopped working. The only thing that happened (I think) in between working and not working was I performed a repair on Microsoft Office 2016 which also wasn't working. The only other vaguely relevant thing is that she had a copy of 32-bit and 64-bit Firefox installed and I uninstalled the 32-bit version.

I have this issue too, but copying VCRUNTIME140_1.dll from another directory doesn't work. Basically what i did was:

• Install
• Error message 'No VCRUNTIME140_1.dll' is displayed
• I opened Firefox, the screen is empty, can't open any webpage or settings
• Got here, looked for VCRUNTIME140_1.dll in my PC, found several
• Copy it to Firefox directory
• Open Firefox again
• Still the same, screen is empty, can't open webpage or settings
• Tried reinstalling using the firefox installer (without uninstalling), still the same

Is there anything more I should do?

farianti.063, have you tried reinstalling a runtime available from here?

I had same problem after uninstall Google Drive from mi PC, you can solve the problem installing this "https://support.microsoft.com/en-in/help/2977003/the-latest-supported-visual-c-downloads" (from a Microsoft official site) and then installing again Firefox. Thanks to @mt3ch!

I had this kind of problem, I tried to install Visual C++ 64 but Windows denied the installation because not found properly folder. I tried with copy of "vcruntime140_1.dll" in Mozilla Firefox Folder but nothing. In the end I unistalled Firefox x64 and I re Installed Firefox x32 (I have a recent HP laptop x64 ....) . Now Firefox it's OK and I can to back with the using of my favorite Browser.

Installing C++ 2019 Redist. (x64) fixed the issue for me (customer's PC)

A customer's PC had the same issue - unable to install Firefox, got "firefox.exe - System Error The code execution cannot proceed because VCRUNTIME140_1.dll was not found. Reinstalling the program may fix this problem." I continued with the Firefox installation but was still unable to navigate to any websites. Also, 2 Firefox processes remains open and need to be manually closed via Task Manager. My post is here: https://support.mozilla.org/en-US/questions/1308396

I was onsite again today with the customer having this problem. With Firefox closed, I downloaded and installed C++ 2019 Redist. (x64) using PatchMyPC. This solved the problem. Able to browse to websites with no problem.

Thanks for the help from this post, it helped me fix my customer's PC. Hopefully Firefox will get this issue resolved soon.