Crash: Updating screen events 'java.lang.RuntimeException: Failed to check session lock, aborting'

Put the summary of the bug you're having here

What I expected to happen was that I would go to an area of the overworld that I had not been before.:

What actually happened was that a new area started to load in and the game crashed, again. This has happened a lot. The launcher will not save my edited profiles or ones that I have deleted. It crashes at least once everytime I try to load a game. I tried adding shaders and Optifine, which I am wondering was my fatel error. I wasn't able to to get either to work and all that has happened is more crashes. I'm starting to wonder if this effecting another game that just so happened to start erroring out and not being able to save.
Describe what happened here

Steps to Reproduce:
1. Load the game.
2. ...
3. ...

Description: Updating screen events

java.lang.RuntimeException: Failed to check session lock, aborting
	at azy.i(SourceFile:64)
	at azy.<init>(SourceFile:50)
	at azv.<init>(SourceFile:21)
	at azw.a(SourceFile:83)
	at bcx.a(SourceFile:2108)
	at bif.e(SourceFile:227)
	at bif.a(SourceFile:182)
	at bif.a(SourceFile:148)
	at bed.b(SourceFile:41)
	at bie.a(SourceFile:118)
	at bft.k(SourceFile:409)
	at bie.k(SourceFile:50)
	at bft.p(SourceFile:386)
	at bcx.t(SourceFile:1586)
	at bcx.av(SourceFile:968)
	at bcx.a(SourceFile:396)
	at net.minecraft.client.main.Main.main(SourceFile:124)

java.lang.NullPointerException: Batching chunks
	at java.util.TimSort.sort(TimSort.java:250)
	at java.util.Arrays.sort(Arrays.java:1438)
	at bnt.a(SourceFile:90)
	at bqy.a(SourceFile:281)
	at bqy.a(SourceFile:123)
	at bqu.a(SourceFile:102)
	at bqu.run(SourceFile:43)
	at java.lang.Thread.run(Thread.java:745)