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I just replaced an SSD drive with a 1TB SSD Drive on my mid 2012 Mac Book Pro. The older SSD drive was my boot drive for over a year but it ran out of space. With the new drive installed I booted from my original HD drive with Sierra installed with the hope of downloading the OS. Instead I get a message that an internal drive can not be read by this computer. I’m asked if I would like to initialize the new drive. I click yes. Disk Utility opens and the new drive is listed but it can’t be mounted. That option is grayed out. Any Ideas? Thanks very much, Steve Gelfand
To start with this series has a known issue with the HD cable. It tends to break down. I would go to an Apple Store or Apple authorized service center to have the cable replaced for Free! As Apple has been quietly replacing them. If that is not an option, here is the IFIXIT guide: MacBook Pro 13" Unibody Mid 2012 Hard Drive Cable Replacement and here is the part you’ll need: MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable Don’t try to run anything until you get the cable replaced as you can do permanent damage to the drive.
