Ubuntu SDK caused login problems for other users on computer

Using Ubuntu-MATE 16.04.2
I installed Ubuntu SDK yesterday, then logged out. All of the other users in the house found they could not login. They select their user, enter their password and click ‘Login’. The PC then hangs and has to be reset. However, I can login, no problem. I uninstalled Ubuntu SDK, logged out and then successfully logged in as another user. I did this for all of the other users.
So what is happening here?