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.

Hi dee.alani, what kind of system were you using before -- was it Windows, Mac or Linux? The location of your old data will vary depending on the OS.

Assuming it was also Windows, make sure you set Windows to show hidden files and folders --

https://support.microsoft.com/en-us/help/14201/windows-show-hidden-files

-- and then check your backup here:

[drive letter]:\Users\username\AppData\Roaming\Mozilla\Firefox\Profiles

(I've bolded Roaming because there is a different set of files under Local, but those are just cached web pages and temporary stuff you can ignore.)

Each folder under Profiles -- typically named with a random part and a text part, like abc1234z.default -- should contain a bookmarkbackups folder. That will have files with the creation date coded into the name -- like bookmarks-2020-11-10_1244_gibberish==.jsonlz4 -- that you can use to restore that backup to your new installation of Firefox. Can you find those?