Unspecified Error when Trying to Install macOS High Sierra
The most likely error is that the disk isn't partitioned correctly. If you have a bootable installer or can connect it in target disk mode - try erasing the entire physical volume again.



In the image above - you want the top item selected and not the volume under the physical drive. I like to click erase and then not make any changes from the defaults - leave the name Untitled or whatever the default name is - not Macintosh HD.

Then when the installer runs, you might need to look at the install log (press command 3 and command L when the install starts) or we'll need to chase down where or if your installer is saved to disk after the install aborted.

In some newer hardware - you need to be connected to the internet with no firewalls so the installer can go get the components for the hardware - perhaps that step is failing and the install log would likely show that.

Here is Apple's full steps on the erase - so choose it over my steps above if mine fail you.


https://support.apple.com/en-us/HT204904