Resolume Alley - Won't start 4K videos

[buffee]

Hi I'm having issues playing 4K clips thru Resolume Alley.
I have tried to reinstall the program and restart the computer but nothing works.
I've had this issue for a while now, hope someone knows how to fix this.

The video clips are in 3840x2160, 30 FPS and rendered from After Effects using DXV3 High Quality No Alpha (same issue with all the different options tho).

Thanks!

Here's a screenshot of how it looks when it opens:

[Zoltán]

Does this only appear with 4k files, or any file?
Only DXV or also h264?

What kind of machine /GPU do you have?