[MC-124094] I can't play singleplayer.

Here is the text I see in the log:

16:38:30	bib	Reported exception thrown!
f: Updating screen events_
	at bib.t(SourceFile:1635)
	at bib.az(SourceFile:1000)
	at bib.a(SourceFile:419)
	at net.minecraft.client.main.Main.main(SourceFile:123)
Caused by: java.lang.RuntimeException: Failed to check session lock, aborting
	at bfb.i(SourceFile:64)
	at bfb.<init>(SourceFile:50)
	at bey.<init>(SourceFile:21)
	at bez.a(SourceFile:84)
	at bib.a(SourceFile:2159)
	at boi.a(Sou_rceFile:212)
	at blk.a(SourceFile:337)
	at boi.a(SourceFile:352)
	at blk.k(SourceFile:400)
	at blk.q(SourceFile:377)
	at bib.t(SourceFile:1625)
	... 3 more