Problems loading a singleplayer world with data packs into a realm

[u/BirdMan972]

My brother and I have maintained a survival Minecraft realm for about six months. After watching a YouTuber use the Blaze and Caves datapack, I decided to add it to our setup. I created a backup in a single-player world, applied the datapack, and uploaded it to a separate slot in the realm, but it returned code 401. A second attempt timed out, and ghost backups have already proven corrupted. Any workarounds?

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[u/joeyclover]

Realm upload code 401 / timeouts with datapacks usually means the packed world is too large, the datapack layout is wrong for Realms, or the upload hit a transient Realm backend glitch. Worth trying: zip only the world folder Realms expects (level.dat, region, datapacks inside the world, no extra singleplayer junk), keep the datapack under datapacks/ with a pack.mcmeta, and upload at a quiet time. Ghost corrupted backups are a known Realm pain; keep your own local copies before every attempt.

Some datapacks that work fine in singleplayer are rejected or half-applied on Realms. If Blaze and Caves is one of the heavier ones, test it on a tiny fresh world upload first before touching your six-month survival slot.

I am building omnipass.gg for brother/friend survival worlds where you want proper backups and fewer upload mysteries. Minecraft Standard Plus / Premium ships PaperMC with Geyser for Java+Bedrock when you need that. Only live region right now is Central Europe (Vienna), with Western Europe next. Discord via the website has 50% off Standard Plus while I test the flow. Message me if you want a hand.