Hi,

If Firefox was used with multiple monitors in the past, please try right-clicking on the Firefox Taskbar icon and Move. Once you Exit (File (Alt + F)), the new settings will hopefully be remembered.

I only have one monitor. So that probably wont work.

Firefox window is too large or opens off screen

see also : Corrupt localstore.rdf

thank you

Please mark "Solved" the answer that really solve the problem, to help others with a similar problem.

I had this problem too, and how I got into it I have no idea. Deleting the file localstore.rdf fixed me right up immediately. Thanks much, ideato. :)

Deleting localstore.rdf fixed my issue as well

Deleting the files will loose your customizations. Another way is to edit the sessionstore.js file, it is found in the same folder as the localstore.rdf

Right click on sessionstore.js - edit - to open in notepad. Then search for the following string

"screenX":"-

What this means is that your firefox browser is showing offscreen. On my file shows "screenX":"-32000","screenY":"-32000","sizemode"

Change the negative screenX and screenY numbers to zero. Save. Then open firefox and everything should be like it was before it went offscreen.