Microsoft includes a feature in Windows 10 and Windows 8 called “driver signature enforcement” feature. They’ll only load drivers that have been signed by Microsoft. To install less-than-official drivers, old unsigned drivers, or drivers you’re developing yourself, you’ll need to disable driver signature enforcement.

Before you begin, keep in mind: Microsoft isn’t just trying to make your life harder here. Driver signing enforcement ensures that only drivers that have been sent to Microsoft for signing will load into the Windows kernel. This prevents malware from burrowing its way into the Windows kernel.

Disable driver signing and you’ll be able to install drivers that weren’t officially signed. Be sure you know what you’re doing! You should only install drivers you trust.

Common Errors Associated With Driver Signature Enforcement :

A Digitally Signed Driver Is Required, Windows requires a digitally signed driver.

OR

A recently installed program tried to install an unsigned driver. This version of Windows requires all drivers to have a valid digital signature. The driver is unavailable and the program that uses this driver might not work correctly. Uninstall the program or device that uses this driver and check the publishers support website to get a digitally signed driver.

OR

In reverse of this, an error for a Steam game appears to deliver the following error:

EasyAntiCheat cannot run if Driver Signature Enforcement has been disabled

To quickly fix the last error mentioned, run these commands from command-line as Administrator and restart Windows for changes to take effect:
bcdedit.exe -set TESTSIGNING OFF
bcdedit.exe -set NOINTEGRITYCHECKS OFF