Every mob died and cloud on land

It is good that you followed the warnings about making backups and not playing in a valuable world in the betas. However, you may need to wait for a future beta before trying that world again (and make a copy first of course).

It is good that you followed the warnings about making backups and not playing in a valuable world in the betas. However, you may need to wait for a future beta before trying that world again (and make a copy first of course).

It is good that you followed the warnings about making backups and not playing in a valuable world in the betas. However, you may need to wait for a future beta before trying that world again (and make a copy first of course).

Similar issue.  My entire world of loaded chunks was thrust upward by 65 blocks.  Mobs stayed in place tho, thus when I loaded the world, all mobs suffocated.  I can swim or walk to new chunks and they are a 65 block drop in y level.  Would create a bug report but this one seems exactly what I'm experiencing.  Waiting on a bug fix with an untouched copy.

Note.  Created a new world to kill time, mined down a bit and discovered a gigantic void around spawn from y - 0 down to void.  about 4-5  chunks wide in every direction from spawn, and nothing spawned beneath y 0. Just empty void.  However beyond that, with render turned up, I can see - y chunks loaded.  

Similar issue.  My entire world of loaded chunks was thrust upward by 65 blocks.  Mobs stayed in place tho, thus when I loaded the world, all mobs suffocated.  I can swim or walk to new chunks and they are a 65 block drop in y level.  Would create a bug report but this one seems exactly what I'm experiencing.  Waiting on a bug fix with an untouched copy.

Note.  Created a new world to kill time, mined down a bit and discovered a gigantic void around spawn from y - 0 down to void.  about 4-5  chunks wide in every direction from spawn, and nothing spawned beneath y 0. Just empty void.  However beyond that, with render turned up, I can see - y chunks loaded.  

Similar issue.  My entire world of loaded chunks was thrust upward by 65 blocks.  Mobs stayed in place tho, thus when I loaded the world, all mobs suffocated.  I can swim or walk to new chunks and they are a 65 block drop in y level.  Would create a bug report but this one seems exactly what I'm experiencing.  Waiting on a bug fix with an untouched copy.

Note.  Created a new world to kill time, mined down a bit and discovered a gigantic void around spawn from y - 0 down to void.  about 4-5  chunks wide in every direction from spawn, and nothing spawned beneath y 0. Just empty void.  However beyond that, with render turned up, I can see - y chunks loaded.