What it means
Factory reset restores a device's local settings, but a vendor service may continue to associate its serial number with a prior owner. Conversely, removing a device from an app may leave physical access codes or stored settings on the hardware until the reset completes.
A real-world example
A buyer resets a used thermostat but cannot add it to a new account because the previous owner never released it from the cloud service.
What to do
Follow the manufacturer's ownership-release instructions, then reset and enroll under the new account. Test that the old login fails and the new one can administer the device.
The distinction that matters
Some locks and alarm systems have safety or contractual transfer steps. Handle these before disabling access. The FTC recommends removing administrative access and personal data as well as resetting equipment, because any single step may leave part of the handover unfinished.
FTC smart-home ownership steps
