Jan Kraetzschmar

I can confirm this still happens in singleplayer hardcore mode in 1.8.

1. Create new world with Game Mode set to Hardcore.

2. Die during gameplay in this world.

3. The Game Over screen with the "Delete world" button appears.

4. Instead of being taken to the main menu, a selection between "Title screen" and "Respawn" is shown.

   • If you choose "Title screen", the world is not deleted. If played from main menu, you get back to step 3.

   • If you choose "Respawn", Minecraft hangs and has to be killed by the OS.

In the latter case, the server log is filled with an endless loop of exceptions thrown:

[Server thread/ERROR]: Couldn't save chunk; already in use by another instance of Minecraft?
aqz: Failed to check session lock, aborting
	at bqm.c(SourceFile:71) ~[1.8.jar:?]
	at aqu.I(SourceFile:2563) ~[1.8.jar:?]
	at bfy.a(SourceFile:107) ~[1.8.jar:?]
	at qs.b(SourceFile:160) [1.8.jar:?]
	at qs.d(SourceFile:231) [1.8.jar:?]
	at qt.c(SourceFile:185) [1.8.jar:?]
	at net.minecraft.server.MinecraftServer.z(SourceFile:599) [1.8.jar:?]
	at net.minecraft.server.MinecraftServer.y(SourceFile:531) [1.8.jar:?]
	at cyk.y(SourceFile:155) [1.8.jar:?]
	at net.minecraft.server.MinecraftServer.run(SourceFile:447) [1.8.jar:?]
	at java.lang.Thread.run(Unknown Source) [?:1.7.0_71]

There is no crash report as the JVM hasn't technically crashed, just stopped responding.