Minecraft crashes when loading a world >0.50MB in size

When loading my Survival world, Minecraft severely lags for about 5-15 minutes, then crashes. The world is about 37.8MB, but when loading my Creative world, which is about 0.04MB, Minecraft lags for about 3 minutes, but then loads the world successfully. In both cases, a background process called Service Host: Web Account Manager starts and sucks up 30-80% of CPU, exhausting Minecraft of resources, causing the lag and crash. This is related, but nowhere near the same as MCPE-36274.