Hi

What happens when you try to bookmark a page? Is there any error message?

it shows error picture attached

Do you have any add-ons installed in Firefox?

What is the security software mentioned in the error message?

how to check those add ons

i have no idea about these add ons

This support article should help:

https://support.mozilla.org/en-US/kb/find-and-install-add-ons-add-features-to-firefox#w_viewing-and-managing-your-installed-add-ons

The second infobar in your screenshot mentions the error that forms the title of the following article. But before taking any drastic action, I have an initial suggestion:

(1) Article: Fix "The bookmarks and history system will not be functional" error message

(2) Integrity check/repair

First, if you haven't already, please do a normal shutdown and/or restart of your system. Restarting Windows can help by freeing up locked files, completing any deferred updates, and resolving temporary file permission issues.

Next, if Firefox still has bookmark problems, could you let us know what you get when you run the "Verify Integrity" diagnosis and repair function. That's here:

Open Firefox's Troubleshooting Information page using any of these methods:

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

Near the bottom, there is a section titled Places Database -- that's the file which stores history and bookmarks. Click the button labeled Verify Integrity. There may be a 10-15 second delay before results appear.

If all is well, the report that appears below the button should start with:

> Task: checkIntegrity
+ The places.sqlite database is sane
+ The favicons.sqlite database is sane
> Task: invalidateCaches
+ The caches have been invalidated
> Task: checkCoherence
+ The database is coherent

Does yours say both databases are "sane" or something else? You can select and copy the report, and then paste it into a reply for review and comment.