Question: Wipe iMac HD through SATA to USB
I recently swapped my original HD in a late 2012 iMac for a SSD. Everything worked well using a Time Machine back up. The one thing I should have done is wipe the original HD before I removed it. I'm attempting to do that now through a SATA to USB cable and am running into a few issues.
The original HD was partitioned with about 900gb for OS High Sierra and about 100gb for Bootcamp. When I plug in the drive with SATA to USB, I don't see anything come up under finder. With Disk Utility, I see another one that says diskOs4 (not the name of my OS partition) grayed out and unmounted and it won't mount if I attempt to.
Is there something I'm missing here or going about this the wrong way?