Steps to reproduce:

Installed 100.0.2 manually. Tried to open and connect to weather,gov. No response. (Note that I use multiple profiles). Installed 100.0 in a different location. Created a brand new profile, everything worked. Ran version 100.0.2 connecting to the profile just created with 100.0. No joy - firefox will not work. Went back to version 100.0. Now that profile no lonter worked. Created another new profile with version 100.0. That worked. So it appears version 100.0.2 is corrupting the profile in some way. Note that I cannot even use settings on versions 100.0.2. This is occuring on a windows 10 laptop. Version 100.0.2 works fine on my windows 11 laptop so it could be something specific to my computer setup. Creating a brand new profile in version 100.0.2 also fails to work.

Actual results:

On version 100.0.2 I just get a blank window. All buttons to the left of the address bar are grayed out. The pocket and hamburger icons on the right are clickable. But clicking on settings does nothing.

Expected results:

Expect the browser to work normally. Please let me know if you want me to try something to help you troubleshoot. I know this isn't alot to go on since it probably works on most computers. I do have a firewall but I have allow rules for firefox and the settings should still work, even if the firewall was blocking the internet.

Hi,

I was unable to reproduce this issue on my end. I've tried it both on Windows 10 and MacOS.

Could you remove every Firefox install you have and download the latest version, create a new profile and check again?
You can find it here: https://www.mozilla.org/en-US/firefox/new/

Thank you!

Attached file is the details after firefox crashed trying to restart in troubleshooting mode

Tried to uninstall, no joy. It will not uninstall. Tried setting up a brand new user in windows thinking that maybe someting in one of the appdata folders was corrupting it. No joy, still will not run. Tried restarting in troubleshooting mode. Crashed on restart. The details are in the attached file. I install firefox from this site: https://www.mozilla.org/en-US/firefox/all/#product-desktop-release. I cannot install from the site you indicated because my admin accounts do not have internet access. I run on a hardened box. Another thing to be aware of is that software cannot run from appdata due to software restriction policies so if the new version now requires DLL's in appdata that would explain the problem, however my windows 11 machine has the same restriction and version 100.0.2 runs fine on it. I know widevine requires DLL's appdata but I do not use firefox for streaming because of that restriction.

I did indicates that once I try to open a profile in version 100.0.2 that I can no longer use that profile in version 100.0. I did find out that the reason is something 100.0.2 added to prefs.js. When I restore prefs.js from a backup created before I use the profile in version 100.0.2 it will work in version 100.0.

I know you don't have alot to go on here. If you think any files or registry entries might help please let me know. I also understand that if I am the only person with the problem it will not be a high priority. When version 101 comes out I will try it and inform you whether or not it works.

Do you use Defender exploit protection or something similar?

You nailed it!! I forgot that I had turned on exploit protection for Firefox on that box. The problem was with the Validate Stack Integrity setting. Turning that off enabled firefox to run.