How to Fix WireGuard "Manager already installed and running" Error in Windows

Recently, I booted up Windows 11 (though I’ve also experienced this on Windows 10) and noticed that the WireGuard client app was missing from my system tray. When I tried to manually start WireGuard, I was greeted with the following error: “Manager already installed and running”.

Not a terribly helpful error and I wasn’t able to find much on it with a quick Google search so I thought I would share how I quickly fixed it in case anyone else comes across this.

Resolving WireGuard “Manager already installed and running” Error

The fix is rather simple- if Windows gives such an error, it obviously thinks that WireGuard is running, right?

So, all we have to do is kill the service in Windows by hitting Ctrl + Alt + Delete, finding the WireGuard Manager service, and then right clicking to stop the service:

Unfortunately, I haven’t been able to identify the root cause of this error. It’s only happened to me twice and I was able to resolve it with these steps.

Hope this helps someone else.

Looks like someone else ran into this issue on Reddit:
Wireguard Windows 11 App disappears from tray. And, if I try to launch it from the Start Menu, it says “Error - Manager already installed and running.” : WireGuard (