Hello,

The Refresh feature (called "Reset" in older Firefox versions) can fix many issues by restoring Firefox to its factory default state while saving your bookmarks, history, passwords, cookies, and other essential information.

Note: When you use this feature, you will lose any extensions, toolbar customizations, and some preferences. See the Refresh Firefox - reset add-ons and settings article for more information.

To Refresh Firefox:

1. Open the Troubleshooting Information page using one of these methods:
   • Click the menu button , click help and select Troubleshooting Information. A new tab containing your troubleshooting information should open.
   • If you're unable to access the Help menu, type about:support in your address bar to bring up the Troubleshooting Information page.
2. At the top right corner of the page, you should see a button that says "Refresh Firefox" ("Reset Firefox" in older Firefox versions). Click on it.
3. Firefox will close. After the refresh process is completed, Firefox will show a window with the information that is imported.
4. Click Finish and Firefox will reopen.

You can try to rename/remove xulstore.json and if present delete localstore.rdf in the Firefox profile folder with Firefox closed.

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Thanks to repliers. I had already tried both remedies with no success.

see this answer:

• https://support.mozilla.org/en-US/questions/1103841#answer-829382

FFus3r said

see this answer:

• https://support.mozilla.org/en-US/questions/1103841#answer-829382

Thanks. Already suggested by another respondent and, in any event, already tried based on my research. Doesn't work.

Back to 61.0.2 for now.

see this answer by cor-el:

• https://support.mozilla.org/en-US/questions/930249#answer-345266

Thanks again to all who tried to help me with this issue. Happy to report version 62.0.2 does not have this problem.

I'm up to 63.0, and I'm still having this problem.

My screen shifts slightly upwards and a bit leftwards frequently -- but not every time -- when I open Firefox. I can shift it to the correct position with the keyboard Shift-Windows-Up Arrow, though it's a pain having to do that so frequently.

And, yes, I've tried junking the xulstore.json file to no avail.