Disable security warning when installing non-certified app.
 

Disable the security warning when installing non-certified application:

To disable the security warning when installing a non-certfied application, set:
HKLM\Security\Policies\Policies\0000101a = 1 (DWORD decimal)
To restore the warnings:
HKLM\Security\Policies\Policies\0000101a = 0 (DWORD decimal)

Note that this makes it easier for any malware to install itself