Minecraft Launcher will not start

Every time I try to start the Minecraft Launcher, it closes instantly without giving out an error message. The icon appears in the dock for a split second, but disappears instantly. Yesterday, upon opening the Launcher it would say "MinecraftLauncher" in the top bar, but I couldn't see the Launcher nor could I close it. I rebooted my PC, after that I couldn't even open the Launcher anymore. I have searched the internet for similar issues, but I couldn't find any. Also, I've tried to open Minecraft in Admin-mode - same result.

I have no idea why this is happening, since Minecraft worked perfectly fine yesterday and I haven't changed anything notable since then.