PZ MP: Missing dictionary script after a Workshop mod dies Build 42

How to fix a multiplayer save that refuses to load because Steam deleted (or you removed) a Workshop mod, without regenerating WorldDictionary.bin and scrambling item IDs. Written from a real Planet Express / Buildable Roofs case.

Symptom

Clients fail while joining. Server logs (or the client console) show:

WorldDictionaryException: [SpriteConfigs] Missing dictionary script on client: Base.SomeModThing
WorldDictionary: Cannot load world due to WorldDictionary error.

The save still marks obsolete SpriteConfig scripts as loaded. The server may tolerate stale entries; clients do not.

Fix overview

What you are looking for

Under the SCRIPTS section header in WorldDictionaryReadable.lua, entries look like:

{
    registryID = 247,
    name = "Base.CFBEAutomaticBrownRoofBottom10WidthFirst",
    version = "4035058024937495098",
    isLoaded = true,
},

Those isLoaded = true scripts are what every client must still provide. For a dead mod, unload them in the binary (optionally mirror isLoaded = false in the readable dump).

Binary layout (B42 script load list)

Names are stored without the Base. prefix when the fulltype starts with Base.. Immediately before the name:

Patch only the flag byte. Do not rewrite names or versions unless you intentionally remap to another existing script of the same string length.

Example Python

Stop the server first. Change PREFIX to your dead mod’s script prefix.

from pathlib import Path
import re
import struct

world = Path("path/to/Saves/Multiplayer/YourWorld")
bin_path = world / "WorldDictionary.bin"
readable = world / "WorldDictionaryReadable.lua"

# Scripts that must no longer be required on clients:
PREFIX = "Base.CFBE"  # change to your dead mod's script prefix

data = bytearray(bin_path.read_bytes())
text = readable.read_text(encoding="utf-8", errors="replace")
marker = "--[[ ---- SCRIPTS ---- --]]"
scripts = text[text.find(marker) :]

pattern = (
    r'\{\s*registryID\s*=\s*(\d+)\s*,\s*name\s*=\s*"([^"]+)"\s*,'
    r'\s*version\s*=\s*"(-?\d+)"\s*,\s*isLoaded\s*=\s*(true|false)\s*,\s*\}'
)

entries = []
for match in re.finditer(pattern, scripts):
    name = match.group(2)
    if not name.startswith(PREFIX):
        continue
    entries.append(
        {
            "id": int(match.group(1)),
            "name": name,
            "version": int(match.group(3)),
            "loaded": match.group(4) == "true",
        }
    )

patched = 0
for entry in entries:
    short = entry["name"][5:] if entry["name"].startswith("Base.") else entry["name"]
    utf = short.encode("utf-8")
    pat = struct.pack(">H", len(utf)) + utf
    offset = 0
    while True:
        found = data.find(pat, offset)
        if found < 0:
            raise SystemExit(f"not found in bin: {entry['name']}")
        version = struct.unpack(">q", data[found - 8 : found])[0]
        if version != entry["version"]:
            offset = found + 1
            continue
        flag_at = found - 8 - 3
        registry_id = struct.unpack(">H", data[found - 8 - 2 : found - 8])[0]
        assert registry_id == entry["id"], (entry, registry_id)
        if data[flag_at] == 0x03:
            data[flag_at] = 0x00
            patched += 1
        break

bin_path.write_bytes(data)
print(f"unloaded {patched} scripts")

Post tip

Lead with the error string so search finds the guide. Call out the do-not-delete-the-bin rule early — that is where most people brick the save.