Vectron

we have multiple problems here. case 1: person uses direct conect to connect to a server, this means the IP+port will be the save directory. person wants to play more...

will fix this

delete the old config file

my best bet is that the image for that area is corrupt. if you know the region that the image is in you could try and delete/move them out and...

crashes can always corrupt things. depending on what the game is doing when the crash happens

if you know the block coordinates or chunk coordinates (both visible on the F3 screen) of the area you can use: [Convert tool](https://dinnerbone.com/minecraft/tools/coordinates/)

try and remove optifine and see if that fixes it.

underground map is never meant to be saved, it functions a bit like a sonar so it only shows you whats around you at that time

it's supposed to be greenish without detail... as for not saving i don't really have a opinion about that my guess is that the original author didn't see a way...

Did this happen when you died? and are you using a modpack so i can try to recreate this crash?