So I saw someone reporting this before me, but you told him it's invalid because this is an issue on his computer and not on Minecraft itself, here I am to prove this is a bug with Minecraft by easy steps:
First proof is really simple, I know alot of players have this problem.
Second one is not a proof, I think this is the reason for this bug:
when you launch Minecraft, a file automatically is created in the logs folder, as I know, the type of file you are using for logs cost money, maybe what happens is that as I load Minecraft, the game is loading and I get a new GZ archive file, the file can't be opened but it must be created to open Minecraft, so the computer is trying to open Minecraft without the GZ file, I don't really know how minecraft launching works but I think replacing the file used to logs may fix the issue... I hope I'm correct...
First of all... what you're talking about has nothing to do with the Minecraft Launcher.
Second of all, I doubt that simply compressing a log file and moving it causes Minecraft to freeze.
If you don't know how Minecraft launching works, why do you know how to improve it?