Well, after I edit with darktable the computer reboots and periodically halts. The first thought I had was that the power supply was failing. But it only happens after running darktable. Is there a way we could nail down what is causing this before I start to just replace parts?

It reboot at about 17:23 and here are the errors it is giving me in dmesg and /var/log/syslog. Does this point you to what it could be?

I don't know what I'm looking at in dmesg and don't know how far back to copy!
Hope this is good.

[   66.482976] [UFW BLOCK] IN=wlp3s6 OUT= MAC= SRC=fe80:0000:0000:0000:2372:3ac4:279c:f220 DST=ff02:0000:0000:0000:0000:0000:0001:0003 LEN=76 TC=0 HOPLIMIT=255 FLOWLBL=1036500 PROTO=UDP SPT=5355 DPT=5355 LEN=36 
[   66.732895] [UFW BLOCK] IN=wlp3s6 OUT= MAC= SRC=fe80:0000:0000:0000:2372:3ac4:279c:f220 DST=ff02:0000:0000:0000:0000:0000:0001:0003 LEN=76 TC=0 HOPLIMIT=255 FLOWLBL=1036500 PROTO=UDP SPT=5355 DPT=5355 LEN=36 
[   66.982905] [UFW BLOCK] IN=wlp3s6 OUT= MAC= SRC=fe80:0000:0000:0000:2372:3ac4:279c:f220 DST=ff02:0000:0000:0000:0000:0000:0001:0003 LEN=76 TC=0 HOPLIMIT=255 FLOWLBL=1036500 PROTO=UDP SPT=5355 DPT=5355 LEN=36 
[   67.394753] [UFW BLOCK] IN=wlp3s6 OUT= MAC= SRC=192.168.0.9 DST=224.0.0.252 LEN=56 TOS=0x00 PREC=0x00 TTL=255 ID=31808 PROTO=UDP SPT=5355 DPT=5355 LEN=36 
[   67.660399] [UFW BLOCK] IN=wlp3s6 OUT= MAC= SRC=192.168.0.9 DST=224.0.0.252 LEN=56 TOS=0x00 PREC=0x00 TTL=255 ID=31837 PROTO=UDP SPT=5355 DPT=5355 LEN=36 
[   67.898448] [UFW BLOCK] IN=wlp3s6 OUT= MAC= SRC=192.168.0.9 DST=224.0.0.252 LEN=56 TOS=0x00 PREC=0x00 TTL=255 ID=31873 PROTO=UDP SPT=5355 DPT=5355 LEN=36 
[   69.425251] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:b0:7f:b9:af:f1:db:08:00 SRC=198.252.206.25 DST=192.168.0.9 LEN=110 TOS=0x08 PREC=0x00 TTL=53 ID=13722 DF PROTO=TCP SPT=443 DPT=41690 WINDOW=60 RES=0x00 ACK PSH URGP=0 
[   71.863569] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:b0:7f:b9:af:f1:db:86:dd SRC=2607:f8b0:4002:080a:0000:0000:0000:200e DST=2600:8807:c007:d200:39b7:9792:f36e:935d LEN=127 TC=0 HOPLIMIT=59 FLOWLBL=550839 PROTO=TCP SPT=443 DPT=50808 WINDOW=114 RES=0x00 ACK PSH URGP=0 
[   72.081655] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:b0:7f:b9:af:f1:db:86:dd SRC=2607:f8b0:4002:080a:0000:0000:0000:200e DST=2600:8807:c007:d200:39b7:9792:f36e:935d LEN=127 TC=0 HOPLIMIT=59 FLOWLBL=868246 PROTO=TCP SPT=443 DPT=50808 WINDOW=114 RES=0x00 ACK PSH URGP=0 
[   72.522503] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:b0:7f:b9:af:f1:db:86:dd SRC=2607:f8b0:4002:080a:0000:0000:0000:200e DST=2600:8807:c007:d200:39b7:9792:f36e:935d LEN=127 TC=0 HOPLIMIT=59 FLOWLBL=645260 PROTO=TCP SPT=443 DPT=50808 WINDOW=114 RES=0x00 ACK PSH URGP=0 
[   73.414368] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:b0:7f:b9:af:f1:db:86:dd SRC=2607:f8b0:4002:080a:0000:0000:0000:200e DST=2600:8807:c007:d200:39b7:9792:f36e:935d LEN=127 TC=0 HOPLIMIT=59 FLOWLBL=16434 PROTO=TCP SPT=443 DPT=50808 WINDOW=114 RES=0x00 ACK PSH URGP=0 
[   75.198980] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:b0:7f:b9:af:f1:db:86:dd SRC=2607:f8b0:4002:080a:0000:0000:0000:200e DST=2600:8807:c007:d200:39b7:9792:f36e:935d LEN=127 TC=0 HOPLIMIT=59 FLOWLBL=892115 PROTO=TCP SPT=443 DPT=50808 WINDOW=114 RES=0x00 ACK PSH URGP=0 
[   77.713042] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:b0:7f:b9:af:f1:db:86:dd SRC=2607:f8b0:4002:0c06:0000:0000:0000:00bd DST=2600:8807:c007:d200:39b7:9792:f36e:935d LEN=123 TC=0 HOPLIMIT=49 FLOWLBL=589661 PROTO=TCP SPT=443 DPT=60286 WINDOW=803 RES=0x00 ACK PSH URGP=0 
[   78.776864] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:b0:7f:b9:af:f1:db:86:dd SRC=2607:f8b0:4002:080a:0000:0000:0000:200e DST=2600:8807:c007:d200:39b7:9792:f36e:935d LEN=127 TC=0 HOPLIMIT=59 FLOWLBL=907299 PROTO=TCP SPT=443 DPT=50808 WINDOW=114 RES=0x00 ACK PSH URGP=0 
[   94.398331] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:b0:7f:b9:af:f1:db:86:dd SRC=2607:f8b0:4002:0c07:0000:0000:0000:005f DST=2600:8807:c007:d200:39b7:9792:f36e:935d LEN=127 TC=0 HOPLIMIT=47 FLOWLBL=624562 PROTO=TCP SPT=443 DPT=48738 WINDOW=207 RES=0x00 ACK PSH URGP=0 
[   98.607223] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 1 failed to flush
[   99.119249] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
[   99.631233] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 1 failed to flush
[  100.751253] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 1 failed to flush
[  101.575244] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 1 failed to flush
[  107.924730] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:b0:7f:b9:af:f1:db:86:dd SRC=2607:f8b0:4002:0c06:0000:0000:0000:00bd DST=2600:8807:c007:d200:39b7:9792:f36e:935d LEN=123 TC=0 HOPLIMIT=49 FLOWLBL=719850 PROTO=TCP SPT=443 DPT=60286 WINDOW=803 RES=0x00 ACK PSH URGP=0 
[  121.012584] [UFW BLOCK] IN=wlp3s6 OUT= MAC=01:00:5e:00:00:01:b0:7f:b9:af:f1:db:08:00 SRC=192.168.0.1 DST=224.0.0.1 LEN=28 TOS=0x00 PREC=0x00 TTL=1 ID=0 PROTO=2 
[  121.014359] [UFW BLOCK] IN=wlp3s6 OUT= MAC=01:00:5e:00:00:01:b0:7f:b9:af:f1:db:08:00 SRC=192.168.0.1 DST=224.0.0.1 LEN=32 TOS=0x00 PREC=0x00 TTL=1 ID=0 PROTO=2 
[  128.885933] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:b0:7f:b9:af:f1:db:86:dd SRC=2607:f8b0:4002:080a:0000:0000:0000:200e DST=2600:8807:c007:d200:39b7:9792:f36e:935d LEN=127 TC=0 HOPLIMIT=60 FLOWLBL=306771 PROTO=TCP SPT=443 DPT=50348 WINDOW=805 RES=0x00 ACK PSH URGP=0 
[  141.538155] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
[  143.058037] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
[  144.217983] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
[  146.714197] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:b0:7f:b9:af:f1:db:86:dd SRC=2607:f8b0:4002:0c06:0000:0000:0000:00bc DST=2600:8807:c007:d200:39b7:9792:f36e:935d LEN=396 TC=0 HOPLIMIT=49 FLOWLBL=1036755 PROTO=TCP SPT=5228 DPT=50620 WINDOW=186 RES=0x00 ACK PSH URGP=0 
[  155.260641] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:78:45:61:24:98:dc:08:00 SRC=192.168.0.3 DST=192.168.0.9 LEN=363 TOS=0x00 PREC=0x00 TTL=64 ID=34450 DF PROTO=UDP SPT=1900 DPT=41602 LEN=343 
[  156.283206] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:78:45:61:24:98:dc:08:00 SRC=192.168.0.3 DST=192.168.0.9 LEN=363 TOS=0x00 PREC=0x00 TTL=64 ID=34451 DF PROTO=UDP SPT=1900 DPT=41602 LEN=343 
[  157.205647] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:78:45:61:24:98:dc:08:00 SRC=192.168.0.3 DST=192.168.0.9 LEN=363 TOS=0x00 PREC=0x00 TTL=64 ID=34452 DF PROTO=UDP SPT=1900 DPT=41602 LEN=343 
[  158.228642] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:78:45:61:24:98:dc:08:00 SRC=192.168.0.3 DST=192.168.0.9 LEN=363 TOS=0x00 PREC=0x00 TTL=64 ID=34453 DF PROTO=UDP SPT=1900 DPT=41602 LEN=343 
[  171.230130] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:b0:7f:b9:af:f1:db:86:dd SRC=2607:f8b0:4002:0811:0000:0000:0000:200e DST=2600:8807:c007:d200:39b7:9792:f36e:935d LEN=127 TC=0 HOPLIMIT=59 FLOWLBL=84030 PROTO=TCP SPT=443 DPT=33268 WINDOW=473 RES=0x00 ACK PSH URGP=0 
[  195.644378] [UFW BLOCK] IN=wlp3s6 OUT= MAC=e4:be:ed:04:95:ca:b0:7f:b9:af:f1:db:86:dd SRC=2607:f8b0:4002:080a:0000:0000:0000:2003 DST=2600:8807:c007:d200:39b7:9792:f36e:935d LEN=127 TC=0 HOPLIMIT=60 FLOWLBL=215363 PROTO=TCP SPT=443 DPT=35348 WINDOW=127 RES=0x00 ACK PSH URGP=0 

What are all of these ufw blocks? Could that be causing the problem?
$ gedit /var/log/syslog could pinpoint the time better. I got a bunch of 'failed to flush' errors (whatever that means

Nov 13 05:13:36 MikesBeast kernel: [ 1223.596512] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:13:36 MikesBeast kernel: [ 1224.044516] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:13:37 MikesBeast kernel: [ 1224.556487] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:13:38 MikesBeast kernel: [ 1225.404496] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 1 failed to flush
Nov 13 05:13:38 MikesBeast kernel: [ 1225.852530] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:13:39 MikesBeast kernel: [ 1226.300515] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:13:40 MikesBeast kernel: [ 1227.124469] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:15:36 MikesBeast kernel: [ 1343.596206] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:15:36 MikesBeast kernel: [ 1344.044183] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:15:37 MikesBeast kernel: [ 1344.556190] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:15:38 MikesBeast kernel: [ 1345.740173] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:15:39 MikesBeast kernel: [ 1346.240181] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:17:01 MikesBeast CRON[5382]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Nov 13 05:17:38 MikesBeast kernel: [ 1465.211830] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:17:38 MikesBeast kernel: [ 1465.711828] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:17:39 MikesBeast kernel: [ 1466.211827] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:19:37 MikesBeast kernel: [ 1584.543436] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:19:38 MikesBeast kernel: [ 1586.039422] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:19:41 MikesBeast dhclient[1664]: DHCPREQUEST of 192.168.0.9 on wlp3s6 to 192.168.0.1 port 67 (xid=0x5da5416b)
Nov 13 05:19:43 MikesBeast dhclient[1664]: DHCPACK of 192.168.0.9 from 192.168.0.1
Nov 13 05:19:43 MikesBeast NetworkManager[1111]: <info>  [1510568383.1866] dhcp4 (wlp3s6):   address 192.168.0.9
Nov 13 05:19:43 MikesBeast NetworkManager[1111]: <info>  [1510568383.1867] dhcp4 (wlp3s6):   plen 24 (255.255.255.0)
Nov 13 05:19:43 MikesBeast NetworkManager[1111]: <info>  [1510568383.1867] dhcp4 (wlp3s6):   gateway 192.168.0.1
Nov 13 05:19:43 MikesBeast NetworkManager[1111]: <info>  [1510568383.1867] dhcp4 (wlp3s6):   server identifier 192.168.0.1
Nov 13 05:19:43 MikesBeast NetworkManager[1111]: <info>  [1510568383.1867] dhcp4 (wlp3s6):   lease time 3600
Nov 13 05:19:43 MikesBeast dbus[1079]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service'
Nov 13 05:19:43 MikesBeast NetworkManager[1111]: <info>  [1510568383.1867] dhcp4 (wlp3s6):   nameserver '68.105.28.11'
Nov 13 05:19:43 MikesBeast NetworkManager[1111]: <info>  [1510568383.1867] dhcp4 (wlp3s6):   nameserver '68.105.29.11'
Nov 13 05:19:43 MikesBeast NetworkManager[1111]: <info>  [1510568383.1867] dhcp4 (wlp3s6):   nameserver '68.105.28.12'
Nov 13 05:19:43 MikesBeast NetworkManager[1111]: <info>  [1510568383.1868] dhcp4 (wlp3s6): state changed bound -> bound
Nov 13 05:19:43 MikesBeast systemd[1]: Starting Network Manager Script Dispatcher Service...
Nov 13 05:19:43 MikesBeast dhclient[1664]: bound to 192.168.0.9 -- renewal in 1749 seconds.
Nov 13 05:19:43 MikesBeast dbus[1079]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Nov 13 05:19:43 MikesBeast systemd[1]: Started Network Manager Script Dispatcher Service.
Nov 13 05:19:43 MikesBeast nm-dispatcher: req:1 'dhcp4-change' [wlp3s6]: new request (2 scripts)
Nov 13 05:19:43 MikesBeast nm-dispatcher: req:1 'dhcp4-change' [wlp3s6]: start running ordered scripts...
Nov 13 05:23:32 MikesBeast ntpd[2333]: 23.239.24.67 local addr 192.168.0.9 -> <null>
Nov 13 05:23:36 MikesBeast kernel: [ 1823.594646] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:23:38 MikesBeast kernel: [ 1825.386631] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 1 failed to flush
Nov 13 05:23:39 MikesBeast kernel: [ 1826.210611] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:25:36 MikesBeast kernel: [ 1943.598219] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:25:36 MikesBeast kernel: [ 1944.046216] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush
Nov 13 05:25:39 MikesBeast kernel: [ 1946.214203] ieee80211 phy0: rt2x00queue_flush_queue: Warning - Queue 2 failed to flush

as for  /var/log/messages that file does not exist. 

--
:-)~MIKE~(-: