Couldn't reopen a World after I had recently logged out of it.

Put the summary of the bug you're having here

What I expected to happen was...:
I closed out of my world called Pre-1.11 because I was experiencing large lag spikes. When I went to reopen the World, I assumed it would load back in completely normal.

What actually happened was...:
When I tried to reopen my World, I would continuously crash my launcher.

Steps to Reproduce:
1. Open the Launcher
2. Run the Launcher
3. Open my Pre-1.11 World and let it load
4. Crashes