Cannot backup files on Win8 hard drive on another PC

I found a way around my issue already, but wanted to ask if anyone else has run into this problem. Here's the scenario:

1. User owns a laptop, but forgot password, and is unable to reset it. This is the "Admin" account, there are no other accounts on the computer.
2. Laptop does not recognize the DVD drive as a bootable drive, but will recognize a USB external thumb drive.
3. User wants system wiped back to factory defaults, but has data that needs to be backed up.
4. Attempts to remove hard drive and connect as external to another computer indicate the drive needs to be "initialized" as MBR or GPT.

My first thought was that the Win7 computer I was using couldn't recognize the Win8 partition (ie. something was updated in Windows that did this.)

But it turns out there's a BIOS setting that disabled booting from CD/DVD, and it was hidden, so I had to find it, enable booting from the DVD, and then I was finally able to boot from my "recovery" disk, back up the user's data (which is actually STILL in progress!!) and tomorrow I will verify the data backup, and then restore the laptop back to factory defaults.

Anyone else experience the need to "initialize" a Win8 hard drive when connecting it to another computer?