1. Click the menu button , click help and select Troubleshooting Information. A new tab containing your troubleshooting information should open.
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.

Note. There is also a help article about this. The help article has an active button that will work from Firefox to do the refresh. Please also note that as stated in the help article this removes your Firefox extensions, you may wish to bookmark all their homepages or download locations to assist you later should you wish to reinstall any of these. (Potentially future versions of Restore / Refresh may automate that also. )

• See and use Refresh Firefox - reset add-ons and settings

Jillly34 said

Firefox is very slow to start so it suggest that I reinitialise Firefox. How do I do this???

I did as you said in your post and, blow me down, it worked!!!!! Firefox start up is faster. Thanks