The problem manifests with random and often (at least once per hour) total system freeze, regardless of what you were just doing. This time around, rather than running back to reverting to 14.04 I did some considerable investigating. The system logs showed nothing -- years ago, apropos a different bug, I would see a crash pattern in the logs with messages like kernel panic as the last entry but that was not the case this time. Next I considered what I was doing last, and opted to switch to firefox over chromium, and the crashes were much fewer. The next suspect was Network Manager ( nm-applet ), just because freezing would occur mostly after the network icon started acting up. With more google searching I found that people had GPU issues when the browsers had hardware acceleration enabled, and I did recall something similar a while back where hardware acceleration was disabled by default to improve stability, but now it was ticked in browser settings to active. The crashes continued, with using Firefox or chrome, but less often. Then I noticed that the forums identifying a bug with ubuntu bay trail, affecting Intel bay trail low end laptops. The bug appears currently unresolved, to do with power states and possibly aggressive power downing.
You can find the discussion and workaround by googling
- open terminal ( Alt+Cntl T )
- copy sudo gedit /etc/default/grub command and past it into the terminal, and enter your admin password
- find the line that looks like
and replace add the extra parameter to look like
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash intel_idle.max_cstate=1"
- save and close
- copy/paste sudo update-grub