Why Firefox Tabs Don’t Sync Even When Sync Is On

Firefox shows your Mozilla account as connected, Sync is on, and still the tabs from your other computer never turn up in Firefox View. Most of the time one sync category is off or the last sync stopped partway.

Open Account and sync on both computers, tick Open tabs in each, then run Sync now on the device that holds the tabs. If the tab list stays empty, reconnect the account and sync once more.

In this guide, I have covered:

Check whether Open tabs is enabled in Firefox Sync

Your Mozilla account is signed in, Sync says it is on, and the tabs from your other computer still do not appear. The usual cause is small: the Open tabs category is switched off, and Sync quietly skips it.

That checkbox has to be on for every computer where the tabs should show up.

1. Click the user profile in the upper-right corner of the Firefox toolbar.
2. Select Account and sync.
3. Find the Open tabs checkbox in the Sync settings.
4. Select Open tabs if it is not already checked.
5. Click Sync now and wait for Firefox to complete the sync.

Close Firefox, open it again, and look at the box once more. It should still be checked. If it has reverted on its own, the account connection is the next thing to test.

Force a manual sync on both computers

The account is connected and Open tabs is ticked, but the tab list on the other computer still looks like it did yesterday. A manual sync pushes the current list right away instead of waiting for Firefox to do it on its own schedule.

Start on the computer that actually has the tabs open. Tabs travel from the device that holds them.

1. Open Firefox on the computer where the tabs are currently open.
2. Click the user profile in the upper-right corner of the Firefox toolbar.
3. Click Sync now.
4. Wait for the sync process to finish before closing Firefox.
5. Open Firefox on the second computer and wait for it to connect to the same Mozilla account.

TIP: Run Sync now on the computer that has the tabs open before you touch the other one. Do it the other way round and there is nothing new to receive.

Synced tabs, once they arrive, sit in Firefox View under Synced tabs. An empty list there means the two devices are not sharing tab data yet.

Open both computers at the same time and use the same Firefox account. If one device is signed into a different account, each account can sync normally without receiving the other account’s tabs.

Reconnect the Mozilla account

The checkbox is on, manual syncs finish without an error, and the tabs still do not move. At that point Firefox’s link to Mozilla’s sync service is worth resetting, and signing the account back in does exactly that.

1. Click the user profile in the upper-right corner of the Firefox toolbar.
2. Select Account and sync.
3. Select Manage Account.
4. Sign in with the Mozilla account that you use on the other Firefox device.
5. Return to Firefox and check that Open tabs remains enabled.
6. Click Sync now.

Give it a minute before you judge the result. The connection and the first data pull both have to finish, then check Firefox View on the second computer.

You’ll know it worked when the tab count in Firefox View matches what is actually open on the other machine.

Check the account and sync settings on the second device

Tabs go one way but never the other, and you are sure the first computer is set up properly. That points at the second device: same browser, different account or a missing checkbox, and nothing will land.

A mismatch on either device can make tabs appear to sync in one direction only.

1. Open Firefox on the second computer.
2. Click the user profile in the upper-right corner of the Firefox toolbar.
3. Select Account and sync.
4. Confirm that the account shown is the same Mozilla account used on the first computer.
5. Check Open tabs in the Sync settings.
6. Click Sync now.

After the sync finishes, open Firefox View and look for the tabs from the first computer under Synced tabs. If they are missing, sign in again with the same account rather than creating a second one.

Reset the Open tabs sync setting

The box was already ticked and you have synced more than once. Toggling the category off and back on forces Firefox to register it again, which clears a stuck state without changing your other account data.

1. Open Account and sync from the Firefox profile menu.
2. Uncheck Open tabs.
3. Click Sync now.
4. Check Open tabs again.
5. Click Sync now and wait for the process to finish.

If the other computer’s Open tabs setting does not match, repeat the same off-on sequence there.

RELATED: Clear Browser Cookies and Cache from the Mozilla Firefox

Additional checks if tabs still do not appear

Tabs are still missing after the reconnect, and both computers have been synced by hand. Compare the account shown in Firefox on each machine before you go any further. Two accounts will each sync perfectly and never meet.

Browsing history and open tabs are separate sync categories, so clearing history is not normally the fix for this problem. If stale site data is part of what you are chasing, our guide to clear browsing history in Firefox covers the cleanup, and you can return to the sync checks afterwards.

For Mozilla’s official troubleshooting guidance, see the Firefox Sync support discussion.