My Firefox browser seems to have reset itself to Windows 8 compatibility. I have Windows 10, 64-bit. Firefox will not open full screen, but opens a tiny, narrow window at the bottom of the screen which I have to use task manager to close. I remember one of the automatic updates coming through a few days ago.
Can I do anything other than uninstalling and a new install? I'd like to keep my favorites list, etc. I am at the extent of my computer skills with this.
Okay, back in Safe Mode, try to set yourself for possible success by making these changes:
(A) Disable Firefox from using hardware accelerated graphics. The steps are in this article:
(B) Disable all extensions you can live without for 4 hours
You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either:
- Ctrl+Shift+a (Mac: Command+Shift+a)
- "3-bar" menu button (or Tools menu) > Add-ons
- type or paste about:addons in the address bar and press Enter/Return
In the left column of the Add-ons page, click Extensions. On the right side, find the "Manage Your Extensions" heading.
If there is at least one extension before the next heading -- "Recommended Extensions" -- please continue:
Then cast a critical eye over the list below that heading. Any extensions Firefox installs for built-in features are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. Most of these probably could be disabled for a few hours without missing out on anything really important, so click their slider switches to disable them.
Any improvement after restarting in normal mode?
No, it would not open.
I followed the instructions and unchecked the boxes for using hardware acceleration and multiple content processes. I set the performance Settings to 1 (which was the lowest. There is no 0.)
I then disabled the four extensions I had, all of which were various security extensions.
I closed safe mode and clicked the regular icon. The same thing happened -an icon at the bottom that shows a small version of the page when the mouse pointer is on it and needs to be closed with the Task Manager.
Hmm, I wonder what else Safe Mode is changing that isn't coming readily to mind. You haven't created a userChrome.css or userContent.css file, have you? Those are disabled in Firefox's Safe Mode as well.
You can create a new profile as a quick test to see if your current profile is causing the problem.
See "Creating a profile":
If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.