Firefox Sync on Windows stuck or not updating? 6 fixes that usually get bookmarks and tabs moving again

Firefox Sync is great when it’s quiet in the background—and incredibly distracting when it gets stuck, lags behind, or stops updating between devices.

Here’s a practical set of fixes for Windows that usually gets Sync moving again without guessing.

Before you start: make sure you’re online, and give Sync a minute after you open Firefox (especially after a Windows wake-from-sleep).

1. Confirm you’re signed into the same Firefox account on every device

Most “Sync is broken” cases are really “two different accounts” (or one device signed out).

• In Firefox, open Menu → Settings.
• At the top, check the email shown under Firefox Account.
• Do the same on your other device(s) and make sure the email matches exactly.

If one device shows “Sign in to sync,” sign back in and allow a few minutes for the first sync pass.

2. Check what Firefox is actually syncing (bookmarks, passwords, tabs)

Sometimes Sync is “working,” but the item you care about isn’t enabled for that device.

• Go to Menu → Settings → Sync.
• Under Choose what to sync, confirm the toggles you need are on (for example Bookmarks, Passwords, Open tabs).
• If you use “Sync everything,” toggle it off and back on once to refresh the selection.

It’s also worth checking whether you’re expecting data that doesn’t sync (extensions and some site-specific settings can behave differently across devices).

3. Force a fresh sync (disconnect and reconnect Sync on Windows)

If Sync is stuck in a bad state, reconnecting is often the cleanest reset—without reinstalling Firefox.

• In Settings → Sync, choose Disconnect… (or sign out).
• Close Firefox completely.
• Reopen Firefox and sign in again to your Firefox Account.
• Leave Firefox open for a few minutes so it can upload/download.

Tip: If you have multiple devices, reconnect one “main” device first (the one with the most complete bookmarks/passwords), then reconnect the rest.

4. Fix Windows time/date and network blocks (a common hidden cause)

Firefox Sync relies on secure connections, and Windows clock drift can break secure sign-in and syncing in subtle ways.

• Go to Windows Settings → Time & language → Date & time.
• Turn on Set time automatically and Set time zone automatically, then click Sync now if available.
• If you’re on a work/school network, try another connection (mobile hotspot) to rule out firewall/proxy filtering.

If Sync works on a different network, the issue is likely a proxy, DNS filter, or firewall rule on the original connection.

5. Clear stuck Sync state by refreshing Firefox (keep your essentials)

If you’ve tried the basics and Sync still won’t behave, a Firefox “refresh” can remove corrupted settings that interfere with account services.

• In the address bar, open about:support.
• Click Refresh Firefox.

This typically keeps core items like bookmarks and passwords, but can remove some customizations (themes, some extensions, and certain settings). After the refresh, sign into Sync again.

6. Check for profile conflicts and duplicate bookmark merges

When Sync restarts after a long gap, you can sometimes see duplicates or “missing” items that were moved.

• Open the Library (bookmarks menu) and search for a bookmark you expect to be missing.
• Look in Other Bookmarks and any recently created folders.
• If duplicates appear, avoid mass-deleting immediately—wait until all devices finish syncing, then clean up on one device and let it sync out.

If you use multiple Firefox profiles on Windows, make sure you’re checking Sync in the correct profile (each profile can be signed into a different account).

Final thoughts

Most Firefox Sync problems on Windows come down to account mismatch, a disabled sync category, or a connection/time issue that blocks secure syncing.

If you work through the steps in order, you usually get back to consistent bookmarks, tabs, and passwords without reinstalling anything.