Not sure if this task is still going, but a quickie just in case. If there is/was a GUI open for this system which has appeared to hang or crash then don't deem that to be a sign of a failed system. I have once seen the GUI hang (freenas 8.3.0 RELp1 x64) when the system was running a test intitiated by the GUI but then left overnight. Why it hung I'm not sure. But under neath it was chugging away just fine. The command line was still fine.
I wouldn't want to you incur another problem if that happened and it caught you out.