How to Recover Firefox Bookmarks, Passwords, and Settings From a Non‑booting Computer

When a computer won’t boot but the hard drive itself is still readable, most Firefox user data can be recovered. Firefox stores a user’s bookmarks, passwords, extensions, settings, cookies and sessions inside a profile folder. If Firefox Sync was enabled on the dead machine, recovery is trivial,  otherwise you’ll need to extract files from the old drive and import them into Firefox on a working computer.

Where Firefox keeps your important files

Firefox stores each user’s data in a profile directory. On different operating systems the path differs, but the most common Windows location is:

C:\Users\<username>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile folder>\

Inside a profile folder the files you care about include:

• Places.sqlite:  contains bookmarks and browsing history (SQLite database).
• Favicons.sqlite:  site icons for bookmarks.
• Logins.json:  saved logins and encrypted password blobs (the current format).
• key4.db (or older key3.db):  encryption key database that Firefox uses to decrypt the passwords stored in logins.json.
• cert9.db:  certificate database used by Firefox (may matter if you exported certificates).
• prefs.js:  your Firefox preferences and many settings.
• extensions and extensions.json:  installed extension data and metadata.
• sessionstore-backups/ (or sessionstore.jsonlz4):  data for currently open tabs and windows.
• handlers.json, search.sqlite, and other small files containing miscellaneous settings.
  

If you find a subfolder whose name looks like xxxxxxxx.default or xxxxxxxx.default-release (random hex then .default), that’s the profile folder. Copying that entire folder gives you everything Firefox stores for that user.

Firefox Sync (best and easiest, if it was enabled)

Before touching hardware, check whether Firefox Sync was active on the dead machine. Firefox Sync synchronizes bookmarks, passwords, history, tabs, and add‑ons to your Firefox Account. If Sync was enabled, you only need to sign into the same Firefox Account on any working machine:

1. Open Firefox on a working computer.
2. Click the account button (or open the menu → Sign in to Sync).
3. Sign in with the same Firefox Account credentials used on the dead computer.
4. Allow it to fully sync. Your bookmarks, stored logins, open tabs, and (most) settings will download.

If Sync is available, that’s the simplest and safest route. If you’re not sure whether Sync was used, continue to the next options.

Remove the drive and attach it to another PC

If Sync wasn’t used or you want a local copy, removing the hard drive is often the fastest way to access the profile folder.

What you’ll need:

• A screwdriver (laptops/desktops vary).
• A SATA‑to‑USB adapter or external enclosure, or another desktop with a spare SATA port.
• A working Windows or Linux PC to read the drive.

Steps:

1. Power down the broken machine and disconnect power.
2. Open the case and remove the drive carefully. If it’s a laptop, consult the model’s instructions.
3. Connect the drive to the working computer using the adapter/enclosure or install it in the spare bay.
4. In the working computer’s file explorer, open the mounted drive and navigate to:
   X:\Users\<olduser>\AppData\Roaming\Mozilla\Firefox\Profiles\
   (Replace X: with the letter assigned to the attached drive.)
5. Copy the entire profile folder (the xxxxxxxx.default-release folder) to the working computer or to an external backup drive. Also copy the profiles.ini file from the Mozilla\Firefox folder,  it helps when restoring.

Copying the entire profile folder preserves bookmarks, passwords, extensions, preferences, and session data. Make at least one backup copy before you start modifying things on the working PC.

Boot the dead computer from a Linux live USB

If you prefer not to remove the drive (or it’s difficult to access), you can boot the computer from a Linux live USB and copy files from the disk without installing anything.

What you’ll need:

• A USB stick (4 GB or more).
• A second computer to create a bootable Linux USB.
• A Linux ISO (Ubuntu or another distribution).

Steps:

1. Create a Linux live USB on another machine.
2. Boot the dead computer from the USB, choose “Try” or live session rather than install.
3. Use the file manager to mount the Windows drive.
4. Find the Firefox profile folder at /mnt/<drive>/Users/<user>/AppData/Roaming/Mozilla/Firefox/Profiles/.
5. Copy the entire profile folder and profiles.ini to a separate USB stick.

This method is non‑invasive and works well when Windows won’t boot but the disk reads fine.

Restoring bookmarks and settings on a working Firefox

Once you have the profile folder copied to a working computer, there are multiple ways to restore bookmarks, settings and extensions.

Option A:  Replace or add the profile:

1. Close Firefox completely.
2. Move the recovered profile folder into the working computer’s Firefox profile directory:
   C:\Users\<youruser>\AppData\Roaming\Mozilla\Firefox\Profiles\
3. Edit profiles.ini in the Mozilla\Firefox folder to point to the recovered profile, or use Firefox’s profile manager to create a new profile and point it to the recovered folder.
4. Start Firefox using that profile. Your bookmarks, extensions and settings should appear.

Option B:  Export/Import bookmarks only:

• If you only need bookmarks, open a working Firefox, go to Bookmarks → Show All Bookmarks → Import and Backup → Restore → Choose File, and use a previously exported JSON/HTML file. If you didn’t export and only have places.sqlite, you can replace the places.sqlite file in your new profile (close Firefox first), then restart.

Option C:  Reinstall extensions manually:

• Copying the extensions folder can pull them in, but Firefox may revalidate or re-download extensions from its store. For a clean restore, reinstall extensions manually after ensuring bookmarks and settings are restored.

Always backup the existing profile on the working machine before replacing any files.

Password recovery

Passwords are sensitive and therefore encrypted. Firefox stores saved logins in logins.json, but the cryptographic keys used to encrypt those logins are stored in key4.db (or the older key3.db). Both files are required to unlock the saved passwords.

Key points about password recovery:

• If you copy both logins.json and key4.db (and the rest of the profile) into a working Firefox profile and there is no master password set in Firefox, Firefox will generally decrypt and display the saved passwords immediately.
• If a Firefox master password (primary password) was set on the original profile, you will be prompted to enter it when Firefox tries to show the passwords. Without that master password, the stored logins cannot be decrypted.
• Historically Firefox’s encryption is managed by the NSS (Network Security Services) system and is largely self‑contained in the profile. Unlike some browsers, Firefox does not commonly rely on the OS user password to decrypt logins. This means copying key4.db + logins.json to another computer usually works — provided a master password is not interfering.
• If you see unexpected failures decrypting passwords after copying the files, double‑check you copied the full profile and used a compatible Firefox version. In rare cases, moving profiles between significantly different Firefox versions causes problems unless you let Firefox upgrade the profile first.

If you encounter a master password you no longer remember: there is no supported way to recover it. The only practical options are restoring from an earlier profile backup made before the master password was set or using an exported password vault you created earlier. Brute‑force or third‑party cracking attempts are nontrivial and may be ethically or legally risky — and often impractical.

If the disk is failing or physically damaged

If you hear clicking, scratching, or the drive is not recognized, stop and consider professional data recovery. Continued attempts can worsen physical damage. For critical data, a specialist lab gives the best chance of recovery, though it can be expensive.

If the drive is readable but very slow, use cloning software that attempts to image the drive to another disk while handling bad sectors (there are tools on Linux and Windows for this). Clone the drive first, and work from the clone; never repeatedly read a failing drive.

Precautions

• Always back up both the original files and the working machine’s current profile before replacing anything.
• If you plan to migrate a recovered profile to another computer, make sure Firefox is fully closed before moving files.
• Keep logins.json and key4.db secure,  they are sensitive. If someone obtains both files and the master password (or no master password is set), they can access your saved credentials.
• If you successfully recover passwords, consider enabling Firefox Sync or exporting passwords to a secure password manager and then turning on a master password or another protection method.
• If you prefer not to remove the drive, booting from a Linux live USB is a safe alternative that requires no hardware changes.

Recovering Firefox bookmarks, passwords, and settings from a computer that won’t boot is usually straightforward: check for Firefox Sync first, then either remove the drive and copy the profile folder or use a Linux live USB to extract the profiles directory. Bookmarks and settings are contained in places.sqlite and prefs.js; extensions and session data are in the profile folder; passwords require both logins.json and key4.db to decrypt and may be guarded by a master password you must know.

With care, backups, and the correct files, a full recovery is commonly possible without specialist help. If the drive is physically failing or passwords are protected by a forgotten master password, you may need professional assistance or may be limited in what can be recovered.