A Mac VPN that disconnects when you lock the screen
Disconnecting a Mac VPN when the screen locks is a trade you should choose, not a surprise. While you are away, your traffic stops crossing the tunnel, and the Mac stops keeping that tunnel warm. When you unlock, it comes back without a second click. The switch belongs off until you turn it on, because a locked screen is not always an idle person.
Locking the screen is not shutting the Mac down
A Mac with the screen locked, or with the display asleep, is still a computer. Processes run. Sync continues. A VPN profile that was connected can stay connected, and for a lot of people that is what they wanted: a download that should finish, a backup that should not wait until morning, a session that should still be there after they step out for coffee.
The other case is the bag. The lid is shut, the display sleeps, and the only traffic left is background chatter from apps that do not know you have left. The tunnel stays up so that chatter has somewhere to go. You pay for that with battery, with a laptop that is warmer than it needs to be, and with a tunnel that is carrying your traffic while you are not there to watch it. Neither case is the “correct” one. They are different jobs. A single default cannot serve both without annoying somebody.
Closing the lid is simply the ordinary way a Mac’s display goes to sleep. The product fact is narrower than the lid: the trigger is screen lock, or display sleep. Unlock is the return.
The trade, stated plainly
Turn the behavior on, and three things become true. On lock or display sleep, the tunnel disconnects. Traffic that would have gone through it stops going through it. On unlock, the tunnel connects again by itself. You do not open the app, find the button, and tap. The menu bar is there if you want to see the state without guessing.
What you give up is continuity across the lock. A large upload that you expected to survive a trip to the kitchen will pause. A call that was up when you locked will not stay up through the tunnel, because the tunnel is gone. If that upload or that call is the point of the afternoon, leave the switch off. The feature is not a virtue. It is a preference about idle time.
What you do not get, and should not pretend you got, is a promise about every packet the Mac might send. The switch disconnects Kovalink’s tunnel. It does not rewrite the rest of the system. Traffic that your routing mode already sends direct still uses the ordinary network, the same as it did before you locked the screen. If you need the longer explanation of that split, it is in how Smart routing keeps local sites direct.
Why it stays off until you opt in
A locked screen is an ambiguous signal. It can mean “I am in a meeting and the laptop is idle.” It can mean “I locked it out of habit and a render is still running.” It can mean “this machine is plugged in overnight and I want it to finish.” Treating every lock as idle would make the third person reconnect, or worse, discover in the morning that the job had been cut off at 6 p.m.
Default off is the conservative reading of that ambiguity. The people who want the drop are able to turn it on once. The people who want a tunnel that survives the lock never have to discover the switch in order to be safe from it. A default that disconnects you is the sort of surprise that gets blamed on the network. This one does not fire until you ask.
Turn it on if your Mac’s idle life looks like this: it rides in a bag, it sits locked between meetings, or it spends the evening closed on a hotel desk. Hotel and trip Wi-Fi is the setting where a warm, chatty tunnel is least useful and a clean disconnect is most. Leave it off if the Mac is a desk machine that works while you do not.
How this relates to battery, and how it does not
An idle tunnel costs energy because it gives the system a reason to touch the network. Dropping it when the display sleeps removes that reason for the hours you are away. That is a real saving on a laptop that would otherwise stay connected in a bag. It is not a measurement of how the machine behaves while you are actively using it with the screen on. Screen-on cost is a different question, and the way to look at the iPhone version of it is in what actually helps VPN battery drain. The Mac-specific notes live under Mac VPN battery drain.
Do not stack folklore on top of the switch. You do not need a second utility to “make sure” the disconnect happened. Watch the menu bar once, lock the screen, unlock, and see the state change. If it did, the feature is doing the only thing it claims.
What Kovalink’s switch actually does
On Mac, the latest version adds Disconnect when idle. It is off by default. Turn it on, and locking the screen or letting the display sleep disconnects the tunnel; unlocking reconnects it. The same version also greatly reduces network wakeups when the device is idle, which is the quieter behavior for the time you stay connected on purpose. The menu bar shows whether you are up. Connect and disconnect remain one button when you want to do it yourself. Auto still chooses a server, or you choose from the Nodes list, and that choice is what gets restored when you unlock.