Fitbit Charge 5 F36 Error Code Fix (Straight-To-The-Point Guide)

Fitbit doesn’t give much detail publicly, but their standard line for F-type boot errors is basically: reboot it, fully charge it, update it, then factory reset it. If that fails, it’s warranty or replacement time.

Do this, in order:

• 1. Give it real power first
  • Use the original Charge 5 cable if you still have it.
  • Clean the metal contacts on the tracker and the charger with a dry cloth or cotton swab. No liquids.
  • Plug the USB into a good wall adapter or a PC USB port you know works.
  • Snap the tracker firmly into the charger. Make sure it’s seated; it should feel locked in, not loose.
  • Leave it charging at least 30–60 minutes, even if the screen is stuck on F36 or totally black.
• 2. Soft restart the Charge 5 (this clears most software glitches)
  • If the screen still responds: swipe to Settings > Device Info (or similar) > Restart Device > confirm Restart.
  • If it’s stuck on the F36 screen but not totally dead, still try tapping and swiping to see if you can reach Settings.
  • After the restart, let it sit on the charger another 5–10 minutes, then check if F36 is gone.
• 3. Force a sync and firmware update with the Fitbit app
  • On your phone, turn Bluetooth off and back on.
  • Open the Fitbit app.
  • Tap your profile icon (top-left) > tap your Charge 5.
  • If you see an Update button or banner, do the update. Keep the tracker on the charger and the phone nearby.
  • If there’s no update option, pull-to-refresh or kill/reopen the app and try again.
  • Once it finishes, check if F36 cleared and the normal watch face shows.
• 4. Full factory reset (Fitbit calls it “Clear User Data”)
  • Warning: This wipes local data on the tracker (recent steps etc.), but your already-synced history in the app stays.
  • If the screen is usable: go to Settings > Device Info > Clear User Data (or Factory Reset) and confirm.
  • Let it reboot. Leave it on the charger until it fully starts.
  • Open the Fitbit app > tap your profile icon > tap the Charge 5 > if needed, choose Set Up a Device and pair it like new.
• 5. Remove/re-add the device in the app (if it still acts weird)
  • In the Fitbit app: profile icon > tap Charge 5 > scroll down > tap Remove This Device and confirm.
  • Close the app, toggle Bluetooth off/on, then reopen the app.
  • Tap Set Up a Device, pick Charge 5, and follow the pairing prompts.
  • If pairing fails repeatedly and the screen still flashes F36, the firmware or main board is probably corrupted.
• 6. Call it: contact Fitbit support
  • If F36 keeps coming back after a full reset and fresh setup, Fitbit’s own playbook is to replace the unit.
  • Check your purchase date and warranty. They’ll usually offer a warranty swap or a discount on a replacement if you’re just out of warranty.
  • There are no official user-serviceable internals on a Charge 5. Past this point, you’re not “repairing”, you’re replacing.