Comment 12 for bug 1186856

I was doing update from 14 to 15 and previously was on lightDM then switch to mdm after upgarde, and it starts showing this message. I'm installing Mint in VirtualBox.

This is what I did to workaround this problem
I discover that the mdm version on official repository is 1.2.5+olivia(which is what I have after upgrade) but the mdm on live CD is 1.3.1, so what I did is boot into live CD and issue the command "sudo dpkg-repack mdm" and copy the package to my machine and install it again then it works.

I'm running Linux MINT 15 KDE x86-64 on VIrtualBox