System : Endeavour OS
Running Chunky through Prism Launcher on 1.21.1

Usecase : trying to pregenerate the server map on my much more powerful personal computer before moving it to our server blade.

Issue : upon running Chunky in any form, either the full command or as segments results in Chunky stopping immediately, it will sometimes show the progress bar and estimate for a second or two and then never again. Trying to start again says that there is a process still running when there isn't, resuming will have it cease immediately as well and any follow up to restart it causes an immediate stoppage. Running as single player or as open LAN doesn't seem to make a difference.

Full Error Log https://mclo.gs/sFSbPPI
brief error log

[13:25:52] [Render thread/INFO] [minecraft/ChatComponent]: [System] [CHAT] [Chunky] Shape changed to circle.

[13:25:58] [Render thread/INFO] [minecraft/ChatComponent]: [System] [CHAT] [Chunky] A task was already started for this world. To continue running it, type '/chunky continue'. To start a new task, type '/chunky confirm'.
[13:26:03] [Render thread/INFO] [minecraft/ChatComponent]: [System] [CHAT] [Chunky] Task started in minecraft:overworld for the circle region centered at 0, 0 with radius 10000.
[13:26:04] [IO-Worker-9/INFO] [minecraft/MinecraftServer]: [Chunky] Task running for minecraft:overworld. Processed: 1601 chunks (0.10%), ETA: 0:01:37, Rate: 16010.0 cps, Current: 48, 24
[13:26:11] [Chunky-minecraft:overworld Thread/INFO] [minecraft/MinecraftServer]: [Chunky] Task stopped for minecraft:overworld.
[13:26:12] [DH-PriorityTaskPicker Thread[7]/WARN] [minecraft/UniformHeight]: Empty height range: [-55 absolute--60 absolute]
[13:26:12] [DH-PriorityTaskPicker Thread[7]/WARN] [minecraft/UniformHeight]: Empty height range: [-55 absolute--60 absolute]
[13:26:12] [DH-PriorityTaskPicker Thread[7]/WARN] [minecraft/UniformHeight]: Empty height range: [-55 absolute--60 absolute]
[13:26:13] [Worker-Main-8/ERROR] [minecraft/ItemStack]: Tried to load invalid item: 'Item must not be minecraft:air'
[13:26:19] [Server thread/INFO] [xy.iw.cr.CreateFiltersAnywhere/]: shutting down extra thread

I'm sorry if you need more information or this is incomplete I've never submitted a ticket to github before. I've seen a few people with this same issue, but they never got to a solution.

You're stopping the task. This would be done either manually or via an integration. I would recommend trying to pre-gen without any other plugins or mods installed to see if the problem still exists.

Please join our Discord server if you need further help troubleshooting, as GitHub is more focused on feature requests and bug reports.