You can check for issues caused by a corrupted or incomplete Visual C++ installation that is missing runtime components (Redistributable Packages) required by Firefox, especially VCRUNTIME140_1.dll.

See "Visual Studio 2015, 2017 and 2019":

• https://support.microsoft.com/en-us/help/2977003/the-latest-supported-visual-c-downloads

thank you, unfortunately that didn't work. do you have any more ideas? It's a bit strange that only edge seems to work and no other browser

Did you try to reboot in case this makes a difference ?

It is possible that your firewall or other security software blocks or restricts Firefox without informing you, possibly after detecting changes (update) to the Firefox application. Remove all rules for Firefox from the permissions list in the firewall and let your firewall ask again for permission to get full, unrestricted, access for Firefox and the plugin-container process and the updater process.

See:

• https://support.mozilla.org/en-US/kb/server-not-found-connection-problem
• https://support.mozilla.org/en-US/kb/Firewalls
• https://support.mozilla.org/en-US/kb/fix-problems-connecting-websites-after-updating

Boot the computer in Windows Safe mode with network support to see if that has effect in case security software is causing problems.

• https://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• https://www.7tutorials.com/4-ways-boot-safe-mode-windows-10

yes I rebootet already several times. also firewall and anti virus was switched off. there are no rules to firefox. all this effects no changes. I also deinstalled firefox and chrome, rebooted, new installation, same effect.

when using Windows Safe mode with network support firefox and chrome started and asked for restoring tabs. then both browsers worked. after reboot. firefox started once, then the same problem occured.

hello alex,

when windows safe mode is launched, this effectively loads "pure" windows and nothing else into memory.

so one of the things you can check out while in "normal" windows are the startups that are launching when the desktop loads.

open startup via start>run>msconfig

then disable all the things that are enable.

then reboot and retry your browsers.

if your browsers work, then it could mean that something in the startup's was interfering with the applications.

HI there,

thank you for your support! All things (except ms) are disabled. Reboot. firefox and chrome started, but only once. After enabling virusprotection and mozilla again, reeboot again, it works again. Hopefully it stays like this.

hello alex,

Thanks for the update. Keep us apprised if the issue arises again.

If it does, think about testing the issue in Windows Safemode w/networking.