Why can my SSD boot into High Sierra
I have an early-2011 MacBook Pro 13" (A1278). I upgraded the RAM to 8GB and installed a 256GB Samsung SSD 850 Pro. I followed the instructions How can I install OS X on a new ssd and after I installed the SSD into the laptop I got the dreaded "question mark".
I then tried other methods of getting the SSD to work when installed in the laptop such as creating a bootable USB thumb drive to install OS X but each time I installed the correctly working SSD into the laptop I got the question mark. I've gone through the MacOSRecovery and see the drive in Disk Utilities and format it correctly, reinstall the OS via the external USB device yet when I go to install the SSD in the laptop the question mark keeps appearing.
I even cloned the existing OS X onto the SSD and booted to the SSD when it was connected to the external USB device and it worked fine then. Again when I installed the SSD into the laptop the question mark appears.
I'm beginning to suspect the SATA cable but it "looks OK". Who knows. I'm about at my wits end with this issued. I spent all day yesterday trying every solution I can find on the internet but to no avail. I'm hoping someone can help with this issue. I know the SSD can't be bad since it installs OS X while connected to the external USB device. I'm almost to the point of returning the SSD and just keeping the HDD that the laptop currently has.
Any help will be appreciated.
Is this a good question?