I use the standard launcher, there is NO second session open. I have to close the game TWICE and relaunch to MAYBE get into a server (standard, vanilla servers), but if I leave the server with the game open, and immediately go back into it, it gives that error as well. Without me having closed the app.

This only began happening since the 1.8.1 update, and every time I open the launcher, I have to sign in again for some reason. I can only sign in with my email, because my username (I changed it a few days ago) is considered "invalid" if I attempt to log in with it. Although, when I log in with my email, my new username is the one that ends up being used when I play.

What's going on? I checked Task Manager (I use Windows), and there are no other Minecraft or Java's open. I'm tired of having to relaunch repeatedly, AND logging in constantly for no reason. I have uninstalled and re-installed Minecraft twice since this began happening.


Most likely your account is using by another person, you may not know him. If this is not a fresh bug. Change password.


If you are playing a LAN game this is likely an issue of adapters overwriting the existing LAN.

Right click on wifi in taskbar - > Open Network and Sharing Center Change adapter settings

Disable all adapters except the one that you are using. In my case I had Wifi for connecting to my LAN.

Not the answer you're looking for? Browse other questions tagged or ask your own question.