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Sudden but orderly shutdowns - fix

Avatar Euan Williams
If you are experiencing sudden but orderly shutdowns at fairly random intervals, several causes have been suggested. Removing the System file > AppleThunderboltNHI.kext < (the driver for Ethernet via Thunderbolt) has fixed the problem here.

Removing this kext from System > Library > Extensions requires using Terminal to temporarily disable System Integrity Protection (SIP). Don’t forget to re-enable SIP afterwards. Only the Ethernet via Thunderbolt connection is prevented from working.

If you later upgrade High Sierra to 13.3 you will have to remove the kext again. Let’s hope that by High Sierra 13.4 Apple will have nailed this bug.

A comprehensive discussion is here and on the five following pages.

Re: Sudden but orderly shutdowns - fix

Avatar Tony Still
Well found Euan, I'm pleased that it's not your hardware.

And you keep telling me that I'm too critical of High Sierra.

Re: Sudden but orderly shutdowns - fix

Avatar Euan Williams
Many users have found High Sierra un-problematic and want to use APFS on their SSDs. I rather have a feeling this issue maybe didn’t turn up during the public beta phase, and may have affected only a few users. For developers these irritations are alarming, but probably not for most of us. In this case Apple’s Genius problem solvers seem to have been caught unawares. Regrettably it happens, but Apple’s Craig Federighi has announced improvements in this area, so there is hope!

For general interest here are some thoughts:
1. Clone your working macOS before installing any major update. Carbon Copy Cloner (Bombich.com) handles Recovery Partitions rather well. A clone can be used to boot up, unlike Time Machine, and is great for Migration Assistant too.
2. Always do health checks before that clone — Safe Boot with a restart to Normal is normally adequate.
3. Never hope that installing an update on top of a faulty System will fix things. It probably won’t, so get everything healthy first to avoid piling problem on problems.
4. The Recovery System will reinstall your previous system version which is convenient.
5. Partitions (APFS: Volumes) allow more than one macOS to be available for boot-up. So if possible have at least two, and use the second one for the Upgrade. That way users can erase whichever one might be outdated or causing grief.

Forensics:
This very truncated account might interest someone in a similar predicament. Following repeated sudden, but orderly, shutdowns, and after all the normal ‘fixes’ (SMC, PRAM resets, fresh system install, erase and reformat, RAM and other hardware fault checks, malware check), the problem persisted, with nothing obvious in the System logs to indicate what was going wrong.

Apple call centre genius suggested a possible logic board issue (later, others said that Apple’s own sophisticated hardware fault software could not detect any issues, but that a new logic board was suggested).

Logic boards being a serious cost, a thorough forensic effort was required. In the end I used macOS Recovery to competely erase absolutely everything on the SSD, software, partitions, APFS volumes. Recovery (which happily was preserved) installed a ‘new’ macOS, and having nothing to refer to, the spinning black and white globe installed the original macOS Mavericks which came with this particular MacBook Pro. (Interestingly, Recovery seems to keep the information required to link up with your wi-fi.)

This produced exemplary smoothness and no mishaps - so no hardware failure. I updated to El Capitan to be clear of any pre-APFS or APFS issues. Result: no mishaps.

By now probably other users would have coagulated their experiences and suggestions on a few technical websites, so I did a very thorough search and concentrated on the site referenced in my previous post, and found three main suggestions:
1. Cores shutting down - use Python script, to keep them idling.
2. Control Video card use
3. Remove: > AppleThunderboltNHI.kext <

Tried #3, and subsequently all has been smooth as butter. Bug report sent to Apple (the more the merrier for an improved High Sierra 13.4).

It is possible that the kext from El Capitan might work properly in High Sierra, it has a different version number, but haven’t tested that. Hope this helps someone.
 
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