Fitbit Charge 5 F33 Fix: Real-World Sync Error Guide

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What This Error Means

F33 on a Fitbit Charge 5 is a sync/connection failure between your tracker, the Fitbit app, and Fitbit’s servers, usually shown as an error code inside the Fitbit app.

In plain terms: the band is on, but the app cannot finish talking to it or the cloud, so sync or a firmware update stalls and throws code F33.

Official Fix

Fitbit never gives a real explanation for F33, but their official checklist for Charge 5 sync and update problems is:

  • Make sure the Charge 5 has at least 20-30% battery. Put it on the charger if in doubt.
  • Keep the tracker within a few inches of your phone while you work on this.
  • Check your phone’s internet: load a web page. If it is slow, switch between Wi-Fi and mobile data and try again.
  • Toggle Bluetooth off and back on in the phone’s settings.
  • Force-close the Fitbit app, then reopen it and pull down to try a manual sync.
  • Restart the Charge 5: on the tracker, swipe down to Settings > Restart Device, and confirm.
  • Restart the phone as well. Power it completely off for 30 seconds, then turn it back on.
  • On the phone, make sure the Fitbit app is allowed to run in the background and is not restricted by Battery Saver or Low Power Mode.
  • Try the sync or firmware update again with the tracker on the charger, phone unlocked, Fitbit app open, and the screen kept awake.
  • If it still fails: in the Fitbit app tap your profile icon, select the Charge 5, choose Remove This Device, then add the Charge 5 again and follow the setup prompts.

If F33 only pops up once in a while, this is usually enough to clear it.

The Technician’s Trick

When F33 keeps coming back, the pairing or app cache is often corrupted. This is how a tech clears it instead of just rebooting all day.

1. Do a clean Bluetooth and app reset

On Android:

  • Open Bluetooth settings and ‘Forget’ every entry that says Charge 5.
  • Go to Settings > Apps > Fitbit > Storage and tap Clear Cache, then Clear Data.
  • Turn the phone completely off for at least 30 seconds, then power it back up.
  • Only now open the Fitbit app, sign in, and use ‘Set up a device’ to add the Charge 5 fresh.

On iPhone:

  • In Settings > Bluetooth, tap the info icon next to Charge 5 and choose Forget This Device.
  • Delete the Fitbit app, then restart the phone.
  • Reinstall Fitbit from the App Store, sign in, and add the Charge 5 like it is new.

2. Hard reset the Charge 5 (last resort)

Only do this if you do not care about unsynced data on the band; it wipes the device completely.

  • Put the Charge 5 on the charger.
  • On the tracker, swipe down to Settings > Device Info.
  • Tap Clear User Data (or Factory Reset) and confirm.
  • Let it reboot, then pair it again from the Fitbit app as a brand new device.

Most stubborn F33 errors die after a full clean pairing plus device reset like this, especially if you also try a different phone and a different Wi-Fi network during setup.

Is It Worth Fixing? (The Financial Verdict)

  • ✅ Fix: F33 only shows during sync or firmware updates, the Charge 5 still turns on, charges, and is under about 3 years old.
  • ⚠️ Debatable: The band is 3-4 or more years old, battery barely lasts a day, and you are already thinking about upgrading features anyway.
  • ❌ Replace: The Charge 5 will not power, will not charge, or keeps throwing F33 even after clean pairing, factory reset, and trying another phone and network.

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