You can remove the JSON files in the bookmarkbackups folder in the Firefox Profile Folder.

• http://kb.mozillazine.org/Profile_folder_-_Firefox

Set the pref browser.bookmarks.max_backups to 0 if you do not want to create JSON backups automatically.

To open the about:config page, type about:config in the location (address) bar and press the "Enter" key, just like you type the url of a website to open a website.
If you see a warning then you can confirm that you want to access that page.
You can use the Filter bar at to top of the about:config page to locate a pref more easily.

Depending on your reasons for asking this, have you considered using the private browsing

• see private browsing
• or if it is because the current default of 10 is excessive following cor-el'slink note you can reduce it to 1 or 2 if preferred.

The matter is. I have to lend my laptop for a month to a colleague. I don't want to uninstall firefox. So , I deleted all my bookmarks.

But , if my colleague navigates to : Bookmarks-->Organise Bookmarks ---> Import & Backup ---> Restore

he will have the ability to bring all of them back again.

There are 5 or 6 entries in this list (with various dates). These entries is what I want to delete permanently.

Then you can remove the.json backups from the bookmarkbackups folder like I wrote above.

• http://kb.mozillazine.org/Backing_up_and_restoring_bookmarks_-_Firefox

Thanks a lot. Finally I found these .json files and deleted them all. Regards George

Please click the Solved It button next to the answer that solved your Firefox support issue, it appears when you are logged in, so this thread gets marked as Solved to help other users who may have this same problem.

You're welcome