I have a problem with my friend’s iMac (mid-2010) that I'm fixing. I’ve replaced his hard drive with an SSD (the Samsung 850 evo) and after reinstalling the OS via recovery mode (cmd+R) it shows a folder with a question mark in it during the boot.
Here's what I've tried so far to fix it:
1) Tried another hard disk (used a 2.5” mechanical drive that I otherwise use for backups) and it worked without the issue on this one.
2)Tried upgrading the sata cable with a new one but it didn’t work.
3)Run First Aid From Disk Utility. The SSD is ok:
4) Tried to select the Startup Disk, but the SSD doesn’t show up! What’s strange is that I can see the SSD in Disk Utility and I was even able to perform the OS installation, but yet it doesn't show up when selecting a startup disk.
5) Tried NVRAM reset (cmd+opt+R+P) but it still doesn't work.
6) Connected the SSD to my PC via a sata to usb cable to check if it works and it works correctly there.
The crazy thing is that I can erase the SSD with disk utility, I can reinstall the OS and at the end of the installation, after the reboot, it still shows the folder with the question mark during boot.
What else can I try to fix the issue?
Here's how the SSD shows up in Disk Utility: