FastAsyncWorldEdit, World Format Issues

What Are FAWE World Format Issues?

FastAsyncWorldEdit processes edits on separate threads to avoid freezing the main server thread. This async approach is what makes FAWE fast, but it also means FAWE must understand exactly how your server stores chunk data. When there is a mismatch between what FAWE expects and how your server actually formats chunks, you get fawe world format issues: corrupted chunks, invisible blocks, lighting glitches, or outright crashes.

These problems most commonly appear after Minecraft version upgrades, when switching server software (Spigot to Paper, Paper to Folia), or when using data packs that modify world generation.

Common Symptoms

• Ghost blocks: Blocks appear to exist client-side but have no collision. Players walk through walls or fall through floors after a FAWE paste.
• Lighting errors: Dark patches or fullbright sections after editing. Chunks show incorrect light levels until you relog or force a relight.
• Chunk corruption: Sections of terrain revert to their pre-edit state after a server restart, or the server logs errors about malformed chunk data.
• Console errors mentioning NMS or adapters: Messages like No adapter found for world format or Unsupported NMS version indicate FAWE cannot communicate with your server's internals.

Diagnosing the Problem

Start by checking your FAWE version and server version:

/fawe version
/version

FAWE releases are tied to specific Minecraft versions. Running FAWE build 2.x.x on a server version it was not compiled for is the most common cause of these problems. Check the FAWE download page or GitHub releases for the build that matches your server.

Check the Config

Open plugins/FastAsyncWorldEdit/config.yml and verify the queue settings:

# config.yml (FAWE)
queue:
  parallel-threads: 2
  target-size: 64
lighting:
  mode: 2          # 0 = none, 1 = basic, 2 = full relight
  delay: true

Setting lighting.mode to 2 forces a full relight after every edit, which fixes most lighting glitches at the cost of slightly slower operations. If you experience chunk glitches after large pastes, reduce parallel-threads from the default to 1 or 2.

Fixing Ghost Blocks

Ghost blocks happen when FAWE updates the chunk data but does not send the update to connected clients. Force a chunk resend:

//resend

If that does not fix it, the issue is usually a chunk section height mismatch. Minecraft 1.18+ uses extended world height (-64 to 320), and older FAWE builds may not handle the new section format. Update FAWE to the latest build for your Minecraft version.

Fixing Lighting Errors

After a large edit, force a relight on the affected area:

//fixlighting

Run this while standing in the affected area. For larger regions, select the area with //wand and use //fixlighting on the selection. Persistent lighting issues across the server often indicate an adapter-level problem, update FAWE rather than relighting manually.

Paper and Folia Compatibility

Paper's chunk system differs from Spigot's, and Folia changes the threading model entirely. FAWE has separate adapters for each platform:

• Paper 1.20+: Use FAWE builds labeled "Paper" specifically. The Bukkit/Spigot build will partially work but causes chunk saving issues.
• Folia: FAWE support for Folia is experimental. Expect chunk handling problems with large async operations. Consider using standard WorldEdit (slower but safer) until FAWE's Folia adapter matures.
• Purpur: Uses Paper's chunk format, so Paper FAWE builds work correctly.

For the base WorldEdit setup and how it compares to FAWE, see our WorldEdit setup guide.

When to Use Standard WorldEdit Instead

FAWE is not always the right choice. If you experience persistent format problems that updates do not resolve, vanilla WorldEdit is the safer option. It processes edits synchronously (which causes brief lag) but uses the server's native chunk handling, eliminating format mismatches entirely. For small to medium edits on servers with fewer than 30 concurrent players, the lag from synchronous editing is barely noticeable.

Summary

Most fawe world format issues trace back to version mismatches between FAWE and your server software. Keep FAWE updated to the latest build for your exact Minecraft and platform version, set lighting mode to full relight, and use //fixlighting and //resend to clean up after large operations. If problems persist, standard WorldEdit is the reliable fallback.

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