Can I get a membership card - I ran into this problem also.

No real solution but I do have a "workaround".
I have a two optical disc desk top that ran windows 7 64-bit for years.
I used CDex for ripping and burning activities. I could open individual instances of CDex for each optical disc.
I updated to Windows 10 64-bit a few days ago and found out CDex would only open one optical disc; multiple instances would only open the same optical disc.
I use the latest CDex (v1.81) that is supposed to be compatible with Windows 10. At least three previous versions back have this same behavior (I tried them)
SO, I tried an alternate software, Fair Stars CD Ripper, which I've also seen good feedback about.
Same behavior - even multiple instances can find only one optical disc.
My workaround is this:
I use CDex v1.81
I open two instances.
In one instance, I open "Settings" and change the setting (doesn't matter if it is selected or not, just change it) for "Use Native NT SCSI".
Like magic, the selected optical disc changes to the other unit.
Then I proceed to do whatever activities I planned with the discs.
Once I close the instances, I have to reuse this same "trick" to use CDex on both optical discs again.
Painful and disappointing, but workable.
"My" opinion is this rather STRONGLY suggests Windows 10 has some fault or at least a significant difference to Windows 7.
FWIW, my optical discs are Plextor PX-B320SA and Asus DRW-24B1ST-i.
Old, but extremely reliable workhorses.
Hopefully somebody out there (Microsoft, are YOU listening?) steps in with a REAL solution.
Makes me wish I was a programmer sometimes instead of a hardware jock.
:)
mlloyd1