Sync rarely fails because of the data itself; almost always it cannot connect or the sign-in expired. Confirm the sync service is reachable, then look at the account state.
Connection issues
Sync needs to reach the service. On corporate networks or behind a proxy, confirm outbound port 443 is not blocked and the proxy is configured correctly.
- Confirm the sync service domain is reachable
- Review proxy and firewall settings
- Test with another network such as a phone hotspot
- Retry with VPN disabled
Account state
After a password change, enabling two-factor authentication or a long period of inactivity, the session expires. Signing in again restores sync.
- Sign out and back in
- All devices must re-login after a password change
- Check for security alerts on the account
- Review the device list in the account center
Data conflicts
Certain items — a very large bookmark folder, or entries with odd characters — can stall sync. Export a backup, clean up the odd entries, then sync again.
- Export a bookmark backup first
- Look for malformed entries
- Sync in stages by disabling history sync
- Reset sync data if it still fails
FAQ
Does resetting sync lose anything?
Resetting clears the cloud copy and re-uploads from this device. Always export a bookmark backup before doing it.
Why do only passwords fail to sync?
Password sync requires verifying your system identity. Until that passes, the item pauses; re-verify to resume.