Chosen Solution

So I have a late 2012 21.5 inch iMac, I got it for free from my school, I’m wondering as they removed the HDD, if I only install an M.2 drive, will the temperature control sensor go off as it does if I don’t use this adapter thing. Or will the iMac ignore that it doesn’t have a normal drive? Sata… Basically, can I leave the SATA and power cable out on the iMac and only have an M.2 drive. Asking so I know before I dump 200 into a 2tb M.2 drive

Your M.2 drive should work just fine. If you use a PCIe slot that’ll save you the hassle and is much faster than the SATA port.