"An error occurred while preparing the installation. Try running this application again." High Sierra

Hi! I'm installing via the network recovery thing with OpenCore . Currently having an issue where the installer will get to about 3mins left, and then throw the error in the title. Happened twice. I followed the fix here, to no effect. My HDD is formatted as macOS Extended (Journaled).

I tried to erase the disk right after this happened the second time, but it said the disk is in use and I can't unmount it.

Other specs; - AMD FX-6300 - GTX 1050 - MSI 970 Gaming Motherboard

Any fix? Thanks in advance!

Author: @JumpscaredByMemes