I get a white screen when opening an app for the first time!

[randoal]

I have just successfully installed High Sierra on my new pc.
And it boots fine and all works well. The only issue is when I install an app and start it for the first time i get a white screen and the hackintosh freezes. I have to manually restart and then when i lunch that app for the second time it works great. This happens for apps downloaded out of appstore. For example this happened when i installed Google Chrome. Sublime Text , Github , xcode....

This is my hardware :

Cpu : i5 4690
MoBo: Gigabyte - GA-H81M-DS2 ( ver 3)
Ram : 4gb 1600 ddr3 ( adding another 4 gb tomorrow )
Gpu : rx 580 4gb

Any help would be appreciated.

 

[BreBo]

@randoal, please update your profile (personal details) with your Motherboard, CPU and iGPU or Graphics Card.

Profiles are mandatory so that others can assist you.