The fastest way is to remove the places.sqlite (History and Bookmarks) file. You will also need to remove the bookmarkbackups folder.

Type about:support<enter> in the address bar.

Under the page logo on the left side, you will see Application Basics. Under this find Profile Folder. To its right press the button Show Folder. This will open your file browser to the current Firefox profile. Now Close Firefox.

Locate the above file. Then rename or delete it. Restart Firefox.

Fred, please confirm that making the above changes DO NOT impact the saved bookmarks of the FF instance in Desktop1?

Also, on Desktop2, should I delete files 'places.sqlite-shm' and 'places.sqlite-wal' as well as places.sqlite? Or leave alone?

Thanks.

FIRST:

On Desktop 2, disconnect from your Firefox Account to stop synchronizing with Desktop 1.

After that, changes on Desktop 2 should not affect Desktop 1.

You can create a separate Firefox Account with a different email address if you want to use Sync or other services on Desktop 2 without synchronizing with Desktop 1.

By the way, I'm assuming those are separate computers.

You can create a new profile. See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

You can possibly transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile