MacBook Pro random shutdown - Thunderbolt?

Kernel Panic Reports are stored at:

/Library/Logs/DiagnosticReports

If you copy and paste that string into:

Finder > Go menu > Go to Folder

it will take you to where those reports are stored.

They are named with Date&Time and start or end in ‘panic’

If you find one, please post the entire most recent report here, by using the “additional text” Icon in the reply footer (looks like a paper with writing).

Please don’t post more about 20 lines of any other types of reports — they are interminable, and any information useful for this purpose is on the first screenful.

Your 2013 model MacBook Pro 15-in has Thunderbolt-2 ports. It is Not subject to the many Thunderbolt issues reported for Apple Thunderbolt-3 ports, especially for Apple-Silicon Macs.

Your report does not show any external drives, but based on what is loaded, I expect that drive is a WDC drive.

Drives like the MyBook came with software, and the manufacturer suggested you install that software.

What that software does is to "spare you the annoyance of having to re-initialize the drive" from its factory set Windows New Technology File System (NTFS) or similar unusual (on a Mac) format. Instead, the software they provided would simulate a MacOS drive inside an NTFS file for your Mac.

The downside of using the manufacturer's software is that if the manufacturer's software is not loaded, the Macintosh Volume may not readable, or may not be writable. This means that in startup manager, Installer, and in Recovery such as after a data loss, the Macintosh Volume may not be visible.

The standard advice given here to all users, including novice users, is to discard the manufacturers software and NEVER use it. "Best Practice" is to erase the physical device when new, using only MacOS Disk Utility, and create the fundamental data structures needed for consistent, reliable use by MacOS.

Be sure to "show all devices" which will allow you to ERASE the entire Physical Device by its immutable manufacturer-given device-name, not just user created Volume-name such as ‘Macintosh HD’.

Each item listed is a text file. You want the most recent one that starts or ends in 'panic', or report that there are none that start or end in panic.

If you identify one, open it and select all the text and copy and paste into the reply window.

to look further, I suggest you download and run this little "discovery" utility, Etrecheck. It fixes NOTHING. its sole purpose is to provide a look into what and how your Mac is running internally. it generates a substantial sanitized report that can be posted back to the forums.

Using EtreCheck to Troubleshoot Potential… - Apple Community

Because I do Not work for Apple, I can blurt out that your specific model computer was seeing some issues with what I called at the time, somnambulance. If not given enough to do, it fell asleep without a trace. There was a third-party haxie available for about ten bucks that would give it a bit more to do, and that fixed the issue. It was reported to Apple.

If the device I see in your pictures is a Ethernet adapter, I suggest you plug it in and connect your Mac via Ethernet. That adapter is fairly needy, and it may provide enough more work to keep your Mac from falling asleep and shutting down.

I think the problem you are seeing is NOT Thunderbolt, but a problem with the drive in that ThunderBolt enclosure.

an ordinary single rotating magnetic drive is not slowed down by a USB-2 bus. it does not require USB-3, and does not require ThunderBolt at all. only when you have created a RAID with multiple drives in an enclosure, or connected SSD drives do you need to think about drive speeds.

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To make progress, I expect you will need to use Recovery Mode to Repair that drive, and if it will not be repaired, to ERASE that drive. You need a plan for how to do that without wiping out your only backup drive.

One way forward would be to obtain an additional Backup drive, make new trusted backups onto the new drive, then explore what is happening with the old drive.

If the old drive can come clean and hold files again, that is your Christmas present.

you have a few fundamental issues showing:

you have turned OFF auto-updates for Apple Security. this means you get no new strings of stuff that MacOS is checking for. You should re-check this box:

System preferences > Software Update > (Advanced) > ...

[√] Iinstall system data files and security updates

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You are running MalwareBytes in constant scanning mode. This can slow your Mac and reduce performance. Users here recommend MalwareBytes for its good ability to scan, ONCE, for Malware. They do not suggest you leave it running all the time.

Also, I apologize, I used the wrong term, 'somnamulance' (sleep-walking) when I meant to say 'narcolepsy' (tendency to randomly fall asleep).

[Link Edited by Moderator]