Direct answer

On 42.20.4, first prove the base game and menu work with mods disabled. Then identify the first item that fails alone, check whether it used the removed loadstring or loadstream methods, update its dependencies, and wait for the author when the error is mod-specific. Never test on the only copy of a valued save.

Do this first

  1. Record the game version and active preset.
  2. Launch a fresh world with mods disabled.
  3. Enable one affected mod and dependencies.
  4. Check the manager and logs for the first clear error.
  5. Add other mods in small batches until the conflict returns.

Installed is not active

Workshop subscription downloads content; the world preset decides what is active. A dependency, incompatibility, version range, or preset change can leave a subscribed mod absent in play.

Find the first failing layer

Start from a clean game and one mod. If that works, investigate the combination, load order, or old world. If it fails alone, use the first relevant log error and current support notes.

  • Clean game fails: verify installation and files.
  • One mod fails: verify version and dependencies.
  • Small preset works: add batches to isolate conflict.
  • New world works: protect the old save and check migration expectations.

After a hotfix

A same-line update can still expose assumptions in a mod. The 42.20.4 security patch specifically removed loadstring and loadstream, so an item that worked on 42.20.3 may need code changes. Keep a working preset record and wait for author or official information when the failure reproduces only with that item.

FAQ

Quick answers

Why is a subscribed mod not showing?

Check that it is enabled in the world's preset, dependencies are active, and it supports the current game version.

Should I delete my save to test mods?

No. Use a disposable world and keep the original backup untouched.

Evidence log

Sources checked

Official sources establish universal facts; forum and specialist sources are used for symptoms, vocabulary, and cross-checking.

Official42.20.4 Stable Security Hotfix

Official 26 August security hotfix for Stable 42.20.4, beta 42.19.2, and legacy41 41.78.21, including removal of loadstring and loadstream.

OfficialFeatures Overview: Build 42.20

Official overview of the expanded map, new towns, basements, animals, crafting, occupations, traits, mod manager, and multiplayer UI.

Specialist guideProject Zomboid Mods Guide

Specialist cross-check for current mod-manager, Workshop, load-order, and multiplayer terminology.

Community report42.20.4 UI Missing With Mods

Recent symptom evidence that a specific UI mod can remove the menu after the hotfix; not proof that every UI failure has the same cause.