Settings → Bluetooth & devices
Remove Microsoft Arc Mouse
Restart PC
Pair again
Resetting Your Foldable Mouse
Power off: Flatten the mouse completely to turn it off.
Remove the batteries: Turn the mouse over, open the battery compartment, and take out both AAA batteries.
Discharge the capacitors: Leave the batteries out for 10–30 seconds to ensure the internal components fully reset.
Reinstall the batteries: Insert both batteries back into the compartment.
Reconnect: Curve the mouse to power it on. If it doesn't reconnect automatically, press and hold the pairing button on the bottom for 5–7 seconds until the indicator light flashes.