When you want to install Windows 10 you might end up with a dreaded BSOD: MULTIPROCESSOR_CONFIGURATION_NOT_SUPPORTED. Help!
 
 
 
 
If you do have multiple processors, then I have bad news for you: dual CPUs need to be identical or Windows can't handle the instructions properly. In practice, this means you'll have to swap one of your CPUs. Contact your hardware supplier.
 
I'm assuming however that you stumbled upon this post because you have a single CPU system and get this error message nevertheless. All the posts I found on the internet concerning this error were indeed referring to multiprocessor systems or, worse, single processor system with a damaged CPU. It shouldn't be like that: perhaps it is only a BIOS setting making trouble.
 
At least, that's what I assumed when I couldn't install Windows 10 after changing motherboard yesterday. Turns out I was right too. There's a setting in your BIOS, in the section about CPUs, called "CPUID Value Limit" or something similar (depends on BIOS manufacturer). My BIOS says it needs to be disabled for Windows XP. As I'm not running Windows XP, I had it enabled without issues through Windows 7 and Windows 8 times. Intel:
 
    The Max CPUID Value Limit in the system BIOS must be disabled for proper processor identification. Once processor identification is complete, the option can be enabled if desired.
 
So I disabled the setting and now I got Windows 10 installed. I didn't enable it again yet - I'll have to look into it to know what its advantages are. The most importing thing, however, is that it solved my issue.