Sorry to hear about this problem. It sounds as though you have worked through this article already: Fix "The bookmarks and history system will not be functional" error message.

Usually removing the places.sqlite file and having Firefox create a new one resolves the issue. If that didn't work, there could be a permissions/privileges problem with your profile folder, or Firefox's program files might be damaged. (The reinstall usually fixes corrupted program files, but there is another way to do it if necessary.)

At this point, could you try setting up a new profile with one of your bookmark backups. This is about a 10 minute project:

(1) Make a bookmark backup file easily accessible

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

• "3-bar" menu button > "?" Help > 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, on the Profile Folder row, click the "Open Folder" button. This should launch a new window listing various files and folders in Windows Explorer.

Double-click into the bookmarkbackups folder. You should see several files with the date included in the file name. Copy one or two of these to a more convenient location such as your Desktop. For example, right-click a backup file and choose Copy. Then click over to the Desktop, right-click > Paste.

(2) Create the new profile

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

Click the Create a New Profile button, then click Next. Assign a name like Oct2018, ignore the option to relocate the profile folder, and click the Finish button.

After creating the profile, scroll down to it and click the Set as default profile button below that profile, then scroll back up and click the Restart normally button. (There are some other buttons, but please ignore them.)

Firefox should exit and then start up using the new profile, which will just look brand new. Please ignore any tabs enticing you to connect to a Sync account or to activate extensions found on your system so we can get a clean test.

(3) Restore bookmarks to the new profile

Following the steps in the following article, you'll see an "Choose File..." option you can use to point Firefox to the Desktop and access the backup file you pasted there.

Can Firefox restore the backup?

(4) Test

Can you use bookmarks and history normally in the new profile?

(5) Next Steps

If bookmarks and history work well in the new profile, I think you have two options:

(A) Migrate important data to the new profile and leave the old one behind. This article has more info:

Restore bookmarks, passwords, and data from an old Firefox profile

(B) Try copying the new places.sqlite in the working profile to your regular profile, replacing the one Firefox is having a problem with. This would be along the same lines you tried before of removing the problem places.sqlite file (and its companion journaling files (-shm, -wal)), but then you could copy in the places.sqlite file from the new profile so Firefox uses that at the next startup.

For the record, this is the recommended reinstall method if you think it might help:

Clean Reinstall

This takes about 5 minutes. It's not about your settings, it's about making sure the program files are clean (no inconsistent or alien code files). As described below, this process does not disturb your existing settings. It's not essential to uninstall Firefox, but you can if you like, saying No to any request about removing personal data.

It only takes a few minutes.

(A) Download a fresh installer for Firefox to a convenient location:

https://www.mozilla.org/firefox/all/

(B) Exit out of Firefox (if applicable).

If you use Microsoft Office, please change your default browser to Internet Explorer temporarily before the next step.

(C) Using Windows Explorer/My Computer (hold down the Windows key and press E to launch it), right-click > rename the program folder as follows (you might have one or both):

C:\Program Files (x86)\Mozilla Firefox =to=> C:\Program Files (x86)\OldFirefox

C:\Program Files\Mozilla Firefox =to=> C:\Program Files\OldFirefox

(D) Run the installer you downloaded in step (A). It should automatically connect to your existing settings.

Any improvement?