I think there is a serious risk that your session history will be cleared, too. However, I haven't tested it yet. If you want to preserve a copy of your session history files while you experiment, you can back them up as follows:

Open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

In the first table on the page, click the "Show Folder" button. This should launch a list of your settings files.

Look for a folder named sessionstore-backups and copy it in its entirely to a safe location such as your Documents folder.

You also should find a file named sessionstore.js which contains your current session windows and tabs. You could back that one up, too, but the recovery.js file in the sessionstore-backups folder should be identical or virtually identical (it may lag a little, but should be updated to be the same fairly quickly).

It has two of 5 session store.js with only two having data . I will keep the two and backup again before I try the forget button .. seems like a dangerous button! Thanks rick =)

I'm concerned about trying it without a few tweaks still ... killing the brain when only the finger hurts and only needs first aid!