I think I understand what you are asking here, but a little unsure about all the situations that you are trying to protect against.

If you are logged into your computer with your normal username and password, then run Firefox, then all of your bookmarks are normally visible. I presume that you are trying to make some of them hidden in an encrypted way; so that someone who can access your machine still cannot see those bookmarks (or copy anything useful to them from your Firefox profile folder)?

I have just been looking at an Add-on called "Private Bookmarks" that will work with the latest Firefox and might serve your purpose:

https://addons.mozilla.org/en-US/fire.../webext-private-bookmarks/

Reading the description, it allows private bookmarks to be held in an Encrypted folder so not only can you not view them in Firefox without using the unlock key, nobody can normally access them via the folder on disk either. I am not sure how good the encryption is or how effiecient the extension is, but it might solve your problem.

Please let us know how you get on.

Thank you, Richard for your prompt reply. That addon which you mentioned apparently does a good job of hiding the bookmarks, allowing me to lock certain ones, keeping them hidden while I am logged in. I may find it useful in keeping my bank account in the Bahamas a secret. :)

However, it may not be needed, as the info I saw in the users folder turns out to be from the "history" urls, which can be easily cleared.

I apologize if this is a duplicate message, but my mail system says it did not go thru the first time.