MacBook Pro mid 2012 dör plötsligt intermittent

Har en Macbook Pro mid 2012 med MacOS High Sierra 2,5GHz 16 GB 1333 MHz DDR3 med en Samsung 840 SSD. Kopplad till en extern 24" Apple skärm, externa apple tangentbord (USB) och en Logitech trådlös mus G602. Kör med datorn ihopslaget stående i en BookArc. För det mesta fungera det utmärkt men rätt som det är utan förvarning blir den externs skärmen svart och datorn svarar inte på något sätt. Kan fås att starta om genom att öppna den och trycka en längre stund på startknappen. Självklart enerverande då ev ej sparat försvinner vid omstart. Kan fungera längre tider ibland flera veckor men så plötsligt - SVART igen.
Någon idé var man skall börja felsöka?

OK, där finns massor. Hjälp att tyda vad som hände när datorn dog 21.31.23

Jul 24 21:30:37 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.imfoundation.IMRemoteURLConnectionAgent): Unknown key for integer: _DirtyJetsamMemoryLimit
Jul 24 21:31:21 MacBook-Pro-13 systemstats[81]: assertion failed: 17G65: systemstats + 914800 [D1E75C38-62CE-3D77-9ED3-5F6D38EF0676]: 0x40
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.WebKit.Networking.391FA72D-16A6-4B7F-AE64-11DADF07AF83[529]): Service exited with abnormal code: 1
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.WebKit.Storage.CAACCF18-25A9-46FC-8F61-1515B7177BEC[599]): Service exited with abnormal code: 1
Jul 24 21:31:22 MacBook-Pro-13 systemstats[81]: assertion failed: 17G65: systemstats + 914800 [D1E75C38-62CE-3D77-9ED3-5F6D38EF0676]: 0x40
Jul 24 21:31:22 MacBook-Pro-13 garcon[399]: Garcon destroyed (0 alive).
Jul 24 21:31:22 MacBook-Pro-13 Finder[329]: BUG in libdispatch client: kevent[mach_recv] monitored resource vanished before the source cancel handler was invoked
Jul 24 21:31:22 MacBook-Pro-13 systemstats[81]: assertion failed: 17G65: systemstats + 914800 [D1E75C38-62CE-3D77-9ED3-5F6D38EF0676]: 0x40
Jul 24 21:31:22 --- last message repeated 2 times ---
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.xpc.launchd.user.domain.502.100008.Aqua): Caller not allowed to perform action: loginwindow.122, action = service removal, code = 150: Operation not permitted while System Integrity Protection is engaged, uid = 0, euid = 502, gid = 20, egid = 20, asid = 100008
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.dropbox.activityprovider[538]): Service exited due to signal: Killed: 9 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.wifi.WiFiAgent[508]): Service exited due to signal: Killed: 9 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.noticeboard.agent[462]): Service exited due to signal: Killed: 9 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 1PasswordAgent[465]: Shutting down 1PasswordAgent 3.8.20 #31499 built Jul 17 2012 08:27:02
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.talagent[326]): Service exited due to signal: Killed: 9 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.coreservices.uiagent[502]): Service exited due to signal: Killed: 9 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.AirPlayUIAgent[456]): Service exited due to signal: Killed: 9 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.maintain.SystemEvents[450]): Service exited due to signal: Killed: 9 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.Logitech.Control Center.Daemon[442]): Service exited due to signal: Terminated: 15 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.CoreLocationAgent[627]): Service exited due to signal: Killed: 9 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.cloudphotosd[353]): Service exited due to signal: Killed: 9 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.Siri.agent[446]): Service exited with abnormal code: 1
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.epson.Epson_Low_Ink_Reminder.launcher[452]): Service exited due to signal: Terminated: 15 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (org.pqrs.karabiner.karabiner_console_user_server[438]): Service exited due to signal: Terminated: 15 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.universalaccessd[324]): Service exited due to signal: Killed: 9 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.imklaunchagent[409]): Service exited due to signal: Terminated: 15 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (org.pqrs.Karabiner-Menu.80284[494]): Service exited due to signal: Killed: 9 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.SystemUIServer.agent[328]): Service exited due to signal: Killed: 9 sent by loginwindow[122]
Jul 24 21:31:22 MacBook-Pro-13 systemstats[81]: assertion failed: 17G65: systemstats + 914800 [D1E75C38-62CE-3D77-9ED3-5F6D38EF0676]: 0x40
Jul 24 21:31:22 MacBook-Pro-13 sessionlogoutd[856]: DEAD_PROCESS: 122 console
Jul 24 21:31:22 MacBook-Pro-13 systemstats[81]: assertion failed: 17G65: systemstats + 914800 [D1E75C38-62CE-3D77-9ED3-5F6D38EF0676]: 0x40
Jul 24 21:31:23 --- last message repeated 4 times ---
Jul 24 21:31:23 MacBook-Pro-13 shutdown[858]: SHUTDOWN_TIME: 1532460683 124816
Jul 24 21:31:23 MacBook-Pro-13 com.apple.xpc.launchd[1] (com.apple.xpc.launchd.domain.system): System shutdown initiated by: shutdown.858<-sessionlogoutd.856<-launchd.1
Jul 24 21:46:18 localhost bootlog[0]: BOOT_TIME 1532461578 0
Jul 24 21:46:53 localhost syslogd[69]: Configuration Notice:

OK tack! Hittat combo 10.13.6

https://support.apple.com/kb/DL1970?locale=sv...

Också info om fördelen med combouppdatering som kan fixa fel

https://www.lifewire.com/use-os-x-combo-updat...

Laddar hem och installerar. Återkommer med besked om det hjälpt.

Har fungerat en tid men nu hände samma sak igen - datorn liksom stänger av sig. Svarar inte på mus eller tangentbord. Får öppnas men när jag trycker på på/av knappen kommer den tillbaka till inloggning direkt - inte den vanliga liggande stapeln så det tycks inte som den stänger av sig helt och hållet.

Några idéer?