Firefox desktop · Research guidance. Instructions are based on publisher guidance; a UK IPTV account was not tested on this platform.
Choose the required outcome
Decide whether you want this browser to stop exchanging information with other devices, to sign out of a Mozilla account or to remove local browser information before handing over a computer. These are separate outcomes. Name the intended one before pressing a button whose label only addresses synchronisation.
Use the current Sync controls
Mozilla’s October 2026 instructions describe Firefox Settings, Sync, Manage Sync and Disconnect, followed by confirmation. The resulting profile stops syncing but remains signed in to the Mozilla account. Read the actual Syncing status afterward instead of assuming that a disconnected sync connection means every account session has ended.
Preserve the local-data distinction
Mozilla explicitly says disconnecting Sync does not delete the profile’s data or settings. If the task is returning a shared computer, that is not enough by itself to establish that local history or saved logins are gone. Review the separately documented sign-out and data-removal options with attention to what will be retained.
Verify the intended boundary
For a synchronisation change, check the account shown, Syncing status and selected device context. For a handover, also inspect ordinary local access after the appropriate cleanup process. Avoid clearing information from other devices unintentionally. A viewing service’s own website login is another session that may need its own deliberate sign-out, using that service’s visible account controls.
Questions, answered
Does disconnecting Firefox Sync delete local data?
No. Mozilla explicitly says it does not.
Does it automatically sign out of the Mozilla account?
No. The documented disconnect action leaves that account signed in.