Can't boot my MacbookPro off an external drive

[aslowdodge]

I have a 2013 MacbookPro 15 in late 2013 with 2.3ghz I7 and 16gb of Ram running Mojave. When I got it used it kept powering off on it's own. Trying multiple things I finally got Nocrash which seemed to help. Now it reboots itself about once ever 2 hours which is somewhat better.

The reason I got this was my 2011 Macbook Pro died and I'm pretty sure it was the graphics that failed.

So I'm trying to use the 2011 Startup drive which has high sierra on it externally to boot the 2013 and while I can select it as a startup drive, it never fully starts up. It starts to boot, but then stops and shuts off.

Any ideas or suggestions?

 

[kohlson]

Probably not the tale you want to hear. I have a 15-in late-2013 MBP, 2.6, 1TB, 16GB.About 3 years after I got it it started rebooting itself.At first, it was the odd thing every 4-6 weeks. One morning at 6am I heard the going while it was just sitting there. Over the next few months it happened more frequently. When it started happening every couple of hours I ran AHT. All fine! But I was able to make an appt. Finally, it stopped booting to home screen. The genius could find nothing wrong -- all tests good!- until it rebooted 2x right in front of him. The answer was a new top case, logic board, and SSD. About $600. Worked like a champ ever since. I'm getting ready tout a new battery in it.

Perhaps use your cMP to create a bootable USB using DiskMaker? If that doesn't work, that confirms you have some serious issues. Note that the SSD is replaceable, if that's the root cause.