The game encounters an unexpected closure due to crash/computer shutting down/etc. while the only player in a single player world is in the nether dimension. Upon returning to the overworld dimension, some massive error occurs in the generation. This has been observed twice. The first time it was observed several chunks near to the nether portal that was used to enter the nether were completely deleted, from build limit to bedrock. The second time it was observed, the player inexplicably died upon reloading the game despite no immanent threats being present upon closure and upon respawning found that the overworld appeared to have been reset to its freshly generated state.