So I'm supposed to be selling my 5k iMac and I was in the process of wiping and reinstalling high sierra. However, I reformatted the drive and well now its completely buggered. I can boot into recovery mode but when the bar fills up, I just get a there was an error and have to restart screen. I tired making a recovery usb and it boots fine but when I click install high sierra it does the same thing and restarts. I'm pretty sure it has something to do with the fusion drive. I'm really stuck and need to try to get this fixed asap! Any help?