They go in:
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Dwm
And the keys are simple, if it’s not there or you delete it, it enables MPO. If it is there, it has a DWORD named OverlayTestMode and a value of 5.
Within the MPO disable .reg:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Dwm]
“OverlayTestMode”=dword:00000005
Within the enable .reg:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Dwm]
“OverlayTestMode”=-
(it removes the key)
As you can see, it’s just a single key and nothing too complex. So using the two .reg files will save you time. Make sure to reboot after changing.