Hi

Thank you for your question about the Firefox Sync service.

It appears from your question, that you are using Firefox Sync as a back up service. This is not what Sync is designed to do. The Firefox Sync service takes a copy of the data you wish to include and transfers it to a second device (typically a mobile device such as a tablet or a telephone) running a copy of Firefox. The storage in between all attached devices is both temporary and fragile and is not stable enough to be (and is not designed as) a reliable backup service.

If you have a copy of your Firefox profile for desktop Firefox, you may be able to recover your bookmarks and other data. Please have a read of this article.

If you have a copy of your data on a mobile version of Firefox, please follow these instructions to connect it to Firefox Sync to copy your data.

Thanks Paul, for the informative reply. I believe the backup is on the previous computer and I do not have a monitor or a way to hook back up to it to download it, so I guess I will just start a new bookmark history on the new computer.

I wanted to ask for your help with that because I'm unable to save a bookmark on it. Whenever I click the star button next to a website to save it as a bookmark it does not react. Thanks for your help.

Yes—Firefox Sync *can* transfer your bookmarks to a new computer, but it only works if your old Firefox profile was syncing correctly before the upgrade. The error you’re seeing (“bookmarks and history system will not be functional…”) means the places database (`places.sqlite`) in your new profile is corrupted or locked, so Firefox can’t load or sync bookmarks. The usual fix is to close Firefox, go to your profile folder, and rename `places.sqlite` and `places.sqlite-shm/wal` so Firefox can create fresh files on restart; once that’s working, Sync should pull your bookmarks down if they were saved to your Mozilla account. If not, you’ll need to recover them from your old Windows 10 profile or a manual backup.

Firefox is having problems working with your "Places" database file(s). That is the source of the error bar you mentioned in your original question ("The bookmarks and history system will not be functional"), as well as the symptom of not being able to save any new bookmarks. You mentioned that you did try some troubleshooting, but it doesn't seem to have worked yet.

Initial question: was this a standard install of Firefox from Mozilla's website, or are you using the version from the Microsoft store? They store their files in different places.

First thing to try is simply exiting out of Firefox and starting it up again. Do you still get the extra toolbar with the error message in the title of the following article: Fix "The bookmarks and history system will not be functional" error message? If you see that bar, Firefox either can't get access to the file -- possibly another process has locked it -- or the file has become corrupted. Before giving up on the file and nuking it (as described in that article), you could try a few other things:

(1) Try to release the file if it's locked

I found a post describing how to use Windows' Resource Monitor to try to figure out what program has opened a "handle" on the file (filter by places): https://superuser.com/a/643312

If it won't release, try a normal shutdown and/or restart of your system. If CCleaner normally runs at startup, see whether you can cancel that or create an exception for Firefox files.

(2) 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: checkCoherence
+ The database is coherent
> Task: expire
+ Database cleaned up

et cetera

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