hi, please go into your firefox profile folder, edit the prefs.js file with a text editor and change/remove the preference you've edited in about:config in the file.

Profiles - Where Firefox stores your bookmarks, passwords and other user data

Hi   ! 'Totally understand your frustration   ! Am I right assuming that you changed the value of the preference 'layout.css.devPixelsPerPx'   ? And now you can't change it back to it's default value, because of the screen size. Telling you to go to the 3-bar menu is pointless;   all I can think of right now is to ask you to try pressing 'Ctrl' and the '-' a number of times.
Does that work   ?

Thank you for reply Philipp. I am in the notepad to make this change. After making the change, do I just close the notepad or save something? Thank you.

philipp said

hi, please go into your firefox profile folder, edit the prefs.js file with a text editor and change/remove the preference you've edited in about:config in the file. Profiles - Where Firefox stores your bookmarks, passwords and other user data

I did try the Ctl and - sign several times and it did not help. I am now trying to do what Philipp suggested and await further inputs from him. Thank you for your help. Will get back to you guys if none work. but I have a feeling Phillipp's suggestion will work.... just am scared to change things and waiting to get more info from the Mod.

Happy112 said

Hi   ! 'Totally understand your frustration   ! Am I right assuming that you changed the value of the preference 'layout.css.devPixelsPerPx'   ? And now you can't change it back to it's default value, because of the screen size. Telling you to go to the 3-bar menu is pointless;   all I can think of right now is to ask you to try pressing 'Ctrl' and the '-' a number of times.
Does that work   ?

yes, please save the changes you have made in notepad, then close the file and try to start up firefox again :-)

philipp said

hi, please go into your firefox profile folder, edit the prefs.js file with a text editor and change/remove the preference you've edited in about:config in the file. Profiles - Where Firefox stores your bookmarks, passwords and other user data

Brilliant advice   !!!

Hoorah...... it worked. I got my Firefox back. Thanks a million!!!!!

philipp said

yes, please save the changes you have made in notepad, then close the file and try to start up firefox again :-)

You need to save the changed file, but you need to take care it is saved with the correct name and that you can see the full name.

The very simplest solution is to try a refresh that should resolve the issue.

• Reset Firefox preferences to troubleshoot and fix problems

Personally I would only suggest you try that if you get stuck. Read that article however as it mentioned file prefs.js

• Also see Reset Firefox preferences to troubleshoot and fix problems

but again it is much better to just edit the file.

If you save the prefs.js file before editing it as prefs js.old that gives you an easy route to reversing changes if necessary. The amended file should be saved as prefs.js NOT as prefs.js.TXT

By default Windows Notepad probably saves files as <name>.txt so you will tend to save a file prefs.js as prefs.js.txt Sometimes Windows hides the part of a name after the dot you need to make sure you can see file extensions;

• See Bleepingcomputer tutorial
  How to show File Extensions in Windows
  https://www.bleepingcomputer.com/tutorials/how-to-show-file-extensions-in-windows/ {Covers XP to 10}

Using the Control key probably will not work because you may have changed the browse Chrome, the bits that are normally the fixed interface

Edit I see it is already solved but I will leave this post here as some users may run in to issues of saving the file under the wrong name. (That may even fix the issue if it renames the file but could then inadvertently reset other things also).