MBP mid 2012 Flashing folder ?

[therealdj]

I have a MBP mid 2012 and had a 500 gb hdd in it and am running out of space. So i went out and got a new drive 1 tb 7200 hgst. I did a data migration and moved everything over to the new drive and it worked great. I was able to boot from outside using a SATA to usb product and the computer boots using the option key. Now when I put the 1tb hdd in the computer all i get is the flashing folder. I put back my old hdd and it boots up perfectly fine. I erased the drive and clone the old drive to the new drive and still the same problem occurs. Honestly I am losing my mind why i cant get this hdd to work. please help.

Macbook pro mid 2012
OSX 10.10.4
500 gb HGST 5400 to 1 tb HGST 7200

 

[chipchen]

For some reason... and this will drive you crazy... but the SATA drive cable is picky, and many of them are defective and do weird things like this. Buy a new one for $30 something off ebay or elsewhere and I bet it will resolve your issue.

 

[BrettApple]

You mentioned that it boots using the option key on startup. You might simply need to go to System Preferences and select the new hdd as the startup drive. Sounds dumb but sometimes OS X won't boot to a disk without one being selected, even though it should. This was true of my '08 MacBook.

I'd give that a shot. If it can't boot from the menu than the drive might not have cloned properly and/or isn't bootable.

And yes, those SATA cables on the 2012 MBPs are pretty infamous for going bad too. I've replaced a handful myself. But it doesn't always make it non-bootable. Mostly IO errors and UDMA CRC counts will go sky high.