Chosen Solution Hi guys, I got stuck with repairing my imac. Here is a little chronology:
iMac 27 “from 2017 quit working, restart using long press on start button. Crossed-out circle symbol after reseach I came to possible defect on SSD or the OS reinstalled (El Capitan) via online recovery mode (cmd + R), updated to Mojave and Time Machine ran stable for a few hours, then the same symbol again and no operation possible —-> opened the imac (that’s the reason the repair shop doesn’t take it to repair) a Samsung 500GB is installed on the PCI port Samsung out, Gigabase adapter and ADATA SX8200 Pro 2 TB (with control screw) in, hard drive looks a bit too high, but goes in … added a isolation tape to protect the adapter from electrical short does not recognize sdd, not even with “diskutil list “in terminal open again, SX8200 out, Samsung EVO 970 EVO 2 TB in does not recognize sdd again, in online restore mode old Samsung (the original ones, if the previous owner didn’t do anything) back in without an adapter, it is recognized (I guess I did not broke anything either) testing comes to the same problem....