Problem details: I just allowed shaders in settings and then my Osu! screen turned black so i can't see anything, I tried closing the app and lauching it again but it didn't work... And also, I'm on Mac
I'm not really too sure how it works on Apple devices but open your osu! folder and edit the osu!.pcname.cfg file with a text editor of some sort and then find the lines Shaders = 1 BloomSoftening = 1, and change the 1 to 0 on both lines and then save the file and launch the game.