Issue with new Minecraft Launcher. 2.0.760

I have switched on Minecraft and the launcher has decided to update to "2.0.760".

Minecraft will launch and I can create a local world but I now cannot connect to my minecraft server. I get the message:

Connection lost
Failed to login: bad login.

I have another pc in my house (not gaming computer) . When I launch minecraft it doesn't upgrade to the new launcher. I can sign into my server fine, so it appears to be an issue with the latest launcher.

My server is hosted on Clanforge.