Issue ticket link Blocks are now completely useless for storage. Need to store a Block for more than one tick? Well, don't, because there is a big chance that the Block becomes completely useless. Blocks can only be used for temporary usage, like using a Block from an Event. It can not be stored in a Collection and can't even be mapped to something, because the Block will eventually 'glitch out' once the chunk it is in, unloads. It was already an issue to store them because worlds could unload, the chunk unloading problem now adds to this. Well, Bukkit has no build-in 'offline' block storage system. You will have to include your own Offline block class to deal with it. In my plugins, I use BlockLocation combined with a BlockMap/BlockSet. If world is unimportant, I also have IntVector3 for storing the x/y/z coordinates. Next time you need to store something: don't use Blocks, ever.