Here's a doozy... strange things are afoot... and I'm hoping for an explanation.
Late last year I did the SSD upgrade, in a mid-2010 MacBook Pro. I took out the optical drive and put it in an external caddy. Then I put a 160 GB SSD in the main drive bay as the startup volume, and put a 750 GB HDD in the optical bay (for large/media files.) Everything's working great. Nice speed boost, no problems with hibernation. Very happy.
Today, I decided I could use more space on the startup drive, so I cloned the 160 GB SSD over to a 512 GB (!) SSD, that was pulled from an early-2011 MacBook Pro. It's Apple branded. And I put that 512 GB SSD drive in my mid-2010 MacBook Pro, in place of the 160 GB SSD.
It starts up fine. But when I get to the desktop, I see that the secondary drive, the 750 GB HDD, doesn't mount. Disk Utility sees it, and reports that it's fine, the Mac OS/Finder just can't mount it. Disk Warrior reports similar issue -- the drive can't be mounted.
And so I put the 160 GB SSD back in the main drive bay, boot the machine, and voila, it's able to mount the secondary drive just fine, just as before.
So what's going on here? Is there some problem with the combination of 512 GB SSD and 750 GB HDD? Why can't I mount the secondary drive when I am booting via the 512 GB (Apple-branded) SSD, but can when I am booting via the 160 GB (third-party) SSD?
Thanks for any feedback.