Loaded in a litematic, even saw the outline of what I had to build. But after a few seconds the game crashed, and every time i reload the world, it crashes within a few seconds. This is the game crash message:

The game crashed whilst unexpected error
Error: java.nio.BufferOverflowException

Any help would be appreciated, thank you.

I think this might have been caused by Optifine. If you didn't solve it yet, then try disabling the Render Regions option in Optifine (which also breaks the rendering anyway...).

issue was resolved on Discord

there should be a crashlog in ./minecraft/crash-reports/

Not sure if this is what you meant by pastebin, just googled it and this is the download it gave me. Hope this helps, thank you Vacla

minecraft_crash_report.txt

Pastebin the full crash log please, that doesn't tell me anything yet really.

Since I'm a retard I deleted both litematica and malilib's jar files so I could play the game, and I lost the crash log. However after seeing your reply I restored them from the recycling bin to see if I could get the crash to occur again. But for some reason everything's working fine now :/

If anything changes I'll let you know, I'm so so sorry for wasting your time on this with my stupidity. Please have a good night.

You can close this issue, and again I'm terribly sorry.