I've got a bug here.
The game will completely crash right after I join a multiplayer server.
It'll work 100% fine on single player. The moment I join any server with or without a shaderpack enabled, it'll crash.
I am also among those that when you download the installer from the official site, you get nothing but malware and security alerts. When you try to run the installer it insists on installing many malware programs that can only be deleted when you boot in safe mode. McAfee WebAdvisor and Malwarebytes both give you security warnings on downloading the installer.
If this is such a great mod like it seems, they shouldn't need to package the installer with the malware. And to the defenders of the malware... yes I got the installer from the official website linked in this forum.