Chosen Solution
I recently installed a new Seagate 1TB SSHD in my MacBook Pro. As described here, I used Super Duper to make a copy of my original hard disk onto the new one, then installed the new hard drive with no problems. However, since installing the new hard drive, my computer freezes randomly - sometimes it’s when I’m typing an email with only one program open, and sometimes it’s when I try to get my computer to do multiple things at once. Is there anything I can do, or is this likely a bad hard drive? I have since gone back to my original hard drive because my computer became unusable.
I would replace the HD/IR cable.
You may need to fix your original HD, using a different boot disk boot up and then run from that disk Disk Utility and make sure you fix both the drive & permissions. If you find you have errors run it again until you have none. The next thing I would do here is make sure the EFI firmware is up to date. Check this Apple TN: # EFi and SMC firmware updates for Intel-based Macs. Lastly, I would try re-cloning the drive after erasing it. That should fix things.
