Minecraft Launcher wont load versions newer than Snapshot 18W16A

Minecraft crashes for me when I load versions newer than Snapshot 18W16A. The launcher loads normally and starts up Minecraft but then Minecraft crashes after a few seconds, before the Mojang logo appears. This issue doesn't occur when I load versions older than Snapshot 18W19A. My computer is running Windows 7 and Java 8 and I have about 500MB of RAM allocated to Minecraft when I load the game.