I see that I didn't note the installed version of unity, when the second crash happened. Oops. Looking at my logs, it probably happened shortly after I upgraded to unity-services 5.8.0-0ubuntu2. Sorry I can't be more sure about that. The crash log is gone from /var/crash, now.
It has not happened again, to date -- about two weeks since the second occurence.
I see that I didn't note the installed version of unity, when the second crash happened. Oops. Looking at my logs, it probably happened shortly after I upgraded to unity-services 5.8.0-0ubuntu2. Sorry I can't be more sure about that. The crash log is gone from /var/crash, now.
It has not happened again, to date -- about two weeks since the second occurence.