hello, can you explain the issue in more details please - is this an error message you're receiving? on which page are you getting it/what are you trying to do before it happens? thank you

It's an error message, I'll attach what I see First one is what I see when I first open up FF

Second is when I click on Tools and select clear history

I read in another thread that the error opening Firefox is a bug that occurs when you close all pages and then quit Firefox. The workaround is to quit with at least one page open.

The second message is unfamiliar. Is Tools > Clear History added by an extension? Perhaps it needs an update or isn't compatible with Firefox 20.

A likely cause of the first issue is that you are first closing all Firefox windows and then close the Firefox application.

Some have reported that closing Firefox (Firefox > Quit) while the browser window is still open works for them.

• Bug 845681 - Closing all windows and quitting Firefox afterwards leads to about:sessionrestore to be shown on next startup

For the second issue try this:

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe Mode start window or otherwise make changes.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes