Involuntary reboot log 8.2

Created 5/9/2016, updated 3/12/2020

Keyboard started acting laggy, so decided to do a preemptive reboot, but got stuck at black screen with spinning progress indicator. After about 20 minutes, hard reset.

Statistics so far

Failure type: hard reset
OS version: 10.11.4
Uptime at moment of failure: probably a week or more
Kernel panics: 1
Hard resets: 1
Total failures: 2
Start of recording keeping: 2 June 2015
Total days to date: 175 days
Average time between failures: 87.5 days

Historical data

For comparison, previous generations of machines (from most oldest to most recent) that I've used have had averages of:

22.73 days (over 1,364 days): iMac (17", Early 2006).
20.06 days (over 321 days): iMac (27", Late 2009).
19.11 days (over 707 days): MacBook Air (13", Late 2010).
41.86 days (over 293 days): MacBook Air (13", Mid-2012).
2.0 days (over 2 days): loaner laptop (MacBook, unsure of model).
27.176 days (over 462 days): MacBook Air (13", Mid-2013).
35.0 days (over 140 days): as above, but with a replacement shell.
Current machine: MacBook Pro (Retina, 15-inch, Mid 2015).