Why won't my MBP boot from the ext SSD
Had 2013 MBP that died. Took out the SSD (with iFixit tools) and put it in an Other World Computing USB enclosure (Envoy). Connects to new MBP 2018 via Other World Computing micro-b usb 3.0 cable with an Apple usb to usb-c adapter. 4 partitions (one aspf and three GUID Mac OS extended journaled) display on the screen and I retrieved the data that was not backed up so that all is well. Running 10.13.5 and 6.
Then thought I would (for the fun of it) try to boot from the now external SSD. Nope. Fails. See the circle with the line (ie no valid system). Have tried both command-R and system preferences. Both offer it as boot option. Have re-installed High Sierra.
Also Disk Utility says the drive is not solid state and is not bootable.
Other World Computing says I need a USB-C to USB Micro-B 3.0 and omit the Apple adapter so have ordered one but...
Why won't it boot? And why does Disk Utility say it is not solid state and not bootable?
Is true, I retrieved my data so should give up, move on, but am now soaked in curiosity.
Ist dies eine gute Frage?