LM 13 - KDE cold boot fine - reoot hangs

[Trio3b]

LM 13 KDE on Toshiba C655. Tried to get installer to use existing partitions on 120gb drive but somehow it installed / and /home on about a 9gb partition that was original used for / with another distro. So / and /home are on one partition.

Maybe that's what's causing this issue. Cold boot is fine, through grub menu, login and desktop. Shutdown and all fine. cold boot later or next day fine.
However, if I select "restart" after a session boot will hang with black screen.

Is there any errata describing this or is it possible that limited disk space with / and /home on a small partition is the issue?

Any help appreciated.