When you upgrade a server to the new snapshot the nether would get corrupted and break into weird chunks of random blocks.
MC-4473
The Nether World Files Gets Corrupted
Resolved
Duplicate
0
Oliver Kristensen
(Unassigned)
Unconfirmed
Snapshot 12w49a
Retrieved
Duplicate of MC-4200 , please use the search function to see if your bug has already been submitted. Currently over 30% of tickets are being closed as duplicate.