OK so just installed a VM at work in VirtualBox using LM 15 Olivia X64 MATE.
Nothing new to see here during install, created myself a user account, specified password twice which obviously matched. Booted up into my new install, would not let me login. Incorrect password apparently..... lol.
So if anyone installs the above version as a VM, please let me know if you get this same issue. Used the same PW I always use, matched it (or it wouldn't let me continue of course) and username was correct as the new login screen has a username list..... First thing I thought was keyboard layout during install, but I checked this and was recognised as UK default, so might be some sort of bug during install to watch out for.
Easily sorted via edit on GRUB to boot up into root shell and change the password on my account and the root account but bit of an annoying fiddle to start things off.