You are trying to install vSphere Update Manager on Windows Server 2012 R2 (whether it is Standard or Datacenter edition) and error appears:
This product can only be installed on Windows Server 2008 or above
In addition to this, your environment meets the following prerequisites:
- The Update Manager server requires a 64-bit Windows system.
- CPU: Intel or AMD x86 processor with two or more logical cores, each with a speed of at least 2GHz
- RAM: 2GB RAM if Update Manager and vCenter Server are on different machines
- RAM: 8GB RAM if Update Manager and vCenter Server are on the same machine
- Network: 10/100 Mbps
- Network: For best performance, use a Gigabit connection between vCenter Update Manager and the ESX/ESXi hosts
Cause
Error says that you have the wrong type of OS , but in fact you have to check is your server domain controller or not. vSphere Update manager on a Microsoft Active Directory Domain Controller is unsupported scenario.
References
Installing VMware vSphere Update Manager fails with the error: This product can only be installed on Windows Server 2008 or above (2078069)
vSphere 6 UM: Supported Operating Systems and Database Formats
UseIT | Roman Levchenko 
Is there a work-around for this?
Hi, Michael!
it’s just officially unsupported. Wizard doesn’t allow you to go into installation.
I’ve not heard about workarounds and never tried to find them (not needed..)
Drat! I’ve had to re-install my machine I had VUM running on, and remembered well after the fact that I needed to install VUM *before* I ran dcpromo on the box, that was the only way to directly get it to work, as it had no problem running on a DC afterwards. The VSphere Client has command-line options you can throw in to skip DC checks, ie: VMware-viclient-all-5.5.0-1281650.exe /VSKIP_OS_CHECKS=”1″ I was wondering if the same would be true for updatemanager.
Why do you want to place UM on DC? Tests – ok. Production – no way. use distributed deployment and leave DC alone 🙂 . P.S. Microsoft won’t support DC running together with VUM as well.