A Firefox backup file can contain more than bookmarks, but the selected options matter. Before replacing a computer, check the actual backup controls available in your installed Firefox version and verify the location of the resulting file.

Review coverage and access together

In Firefox Settings, look under the account or sync section for backup controls. Labels and availability vary by version and platform. If the feature is absent, consult Mozilla’s current compatibility notes and use a supported export or profile-backup method instead of assuming an unseen backup exists.

Choose a destination you can access from the replacement computer. Mozilla distinguishes basic backup data from sensitive items such as saved passwords and payment methods. Including sensitive data requires password protection. Store that backup password separately from the computer being retired; keeping it only inside the browser you are trying to restore defeats the recovery plan.

Check the file, then the recovery result

Find the backup in the selected location and inspect its date. If the folder synchronises to a cloud service, confirm that the file has reached the correct account. A local path inside a sync folder does not by itself establish that the remote copy is current.

Preserve any new browser information on the destination before performing a restore. After restoring, check representative bookmark folders and the categories you deliberately included. Keep the old computer intact until the new workflow works and another recoverable copy exists.

Mozilla’s turn-off control also deletes the backup file. Do not switch backup off merely to tidy the old setup before safeguarding the copy you need. A refreshed backup is useful for migration, while retaining dated independent copies can help when you need an earlier state.

Source: Mozilla Support.