Acrobat X Pro never stays running, keeps asking me to license the software., even though I did

I installed the Creative Suite 6 Master Collection upgrade on a Windows 10 machine, and among the progams is Acrobat Pro X. When I start Acribat Pro X, it closes after a few seconds and a dialog box pops up saying my trial will expire in 32767 days. I click the "License this software" button, log in, and enter the CS6 serial number (there is no separate serial number provided for Acrobat Pro X) where I'm asked for a serial number. I click the  'Next' button and the dialog closes. Then I start Acrobat X Pro again and the same thing happens. No matter how many times I go through this process, Acrobat Pro X never stays open. Adobe Support used Remote Access to download a new set of CS6 install files, and reinstalled everything. That still didn't fix it. They gave up and sent me here. Any ideas?

P.S. Since the CS6 is an upgrade, I tried installing the software when I've got a licensed copy of Acrobat Pro 9 installed. That didn't change the behavior. 

P.P.S. Since 32767 days is 89 years, I tried just saying to continue the "trial". Didn't work, Acrobat Pro X kept doing the same thing.