CS6 Design Standard (disk) Genuine Software Verification Failure

I have Adobe Creative Suite 6 Design Standard, student edition, Mac, on an install disk.

This software has been installed on my computer once.

I then uninstalled the software and switched to Creative Cloud for my work.

Now I've uninstalled CC and am trying to reinstall the CS6. I don't want to continue paying for CC when I have CS6 and it (previously) worked fine.

When I try to reinstall CS6, the installation gets to 2% and then says it appears to be a counterfeit version. I purchased this through my university at the Adobe/Mac reseller store and have registered the software / have the serial number.

Things I've tried:

• Installing CS6 as a trial

• Using the Adobe CC cleaner / uninstaller

• Steps listed in this forum

I've read almost all forums on this top, have googled a lot, and nothing has worked.

Any guidance is appreciated. I've spent 2 days trying to install this software.