Minecraft 1.13 Freezes & Crashes on Startup

Minecraft Launcher opens perfectly & is completely usable. Upon clicking the "Play 1.13 - Latest Release" button, Minecraft opens in a frozen state and gets as far as the title screen. Unable to click anything or even maximize the window as the game is frozen and stays frozen. I also have Optifine & Forge installed; if these cause errors with 1.13 for some reason I will uninstall. No crash reports.