Comment 40 for bug 1535058

@serge a couple of things that could be preventing your login of unity8

1) Upgrade your system. Verify you have Mir 0.19.0 installed and then remove some broken packages that _will_ make Unity8 crash:
  $ sudo apt-get remove mir-client-platform-mesa3 mir-client-platform-mesa2 mir-client-platform-mesa1
you should be on mir-client-platform-mesa4

2) Exercise your arm. We presently block for up to 30 seconds waiting for the kernel entropy pool to get populated (which may not happen). After 30 seconds, if it hasn't then Mir will give up and crash. Presently this is considered a "security feature" but we're improving on it. The workaround is to move your mouse around furiously both before and during the login process.
(https://bugs.launchpad.net/mir/+bug/1536662)

3) unity8 is supposed to be on vt8, but double check vt9 and see if unity8 is there, for some reason, i see it on vt9 not vt8 - i discovered on accident in frustration flipping between vts

4) this bug may also get you https://bugs.launchpad.net/ubuntu/+source/clutter-gst-3.0/+bug/1525285 causes a deadlock

lastly, how to find unity8 login (which i've always found hard to explain in words) for those that may want to try
http://www.youtube.com/watch?v=W4Ijz8QSMJM