I tried to install High Sierra but I upgraded my internal SSD to an OWC Aura. When I try and do the install it says I don't have the proper partition. I was told that I need to reinstall the original drive, do the install and then put the OWC SSD back in and then it will let me install High Sierra on the Aura. Seems pretty convoluted to me?
Doesn't sound right, I assume you have a MP6,1. I don't see how installing the original drive is going to help, because you have to pull it back out to reinstall the OWC drive?
That won't change the data on the installer, I'm sure I'm missing something, but last time I checked computers don't run on magic.
[doublepost=1528367182][/doublepost]Maybe you are trying to run the installer by opening it and it's giving you some error about partitions?
Best to make a bootable USB stick with the installer.
Install Disk Creator
BACK UP YOU DATA.
I know this maybe a hard step, as I have no idea how much data you have, and you external drives are not working correct. You maybe able to backup your data to iCould, or get a USB3 drive for this. I know that sucks, but you really need to do a format and install, not just run the installer, because for some reason I ran the installer twice the other day, and it gives no option to archive and install, and doesn't replace everything the OS runs on.
Once you have backed up you data, boot the USB installer by holding the option key at boot time and selecting it. Once the installer boots, you will have a menu at the top of the screen where you can select the disk utility, open it and erase the OWC drive and format it APFS( or HFS+ Journaled if you need to maintain backward compatibility for some reason, not recommended ).
Once the disk has been erased and formatted, quit the disk utility and continue the install, you should now be able to select your OWC SSD as the place you want to install.
Let us know if that doesn't work.