ZombieBuddy: GitHub download, install, update and uninstall

Find the correct GitHub download

The author repository is zed-0xff/ZombieBuddy. Open its Releases page through the repository and distinguish the Windows installer asset from the framework release. “Zombie Buddy GitHub” is a spaced search phrase for this same project, not another required dependency.

Avoid a similarly named repository or a repack linked in a comment. If GitHub initially hides the asset list, reload the official release page and expand Assets. Do not treat a source-code archive as a ready-to-run Windows installer.

Source: ZombieBuddy · GitHub README · Framework author documentation

Check the game build and loaded framework version

The author Workshop currently lists B41 and B42.12–B42.21. A dependent mod can have a narrower requirement: a loader supporting B41 does not make a Build 42 camera mod run on B41. For another game patch, check the latest author notes before assuming the same recipe applies.

Make a note of the exact game patch, loader version shown during startup, installer release and dependent-mod versions. Use that record when comparing instructions. An installer’s version number is not the ZombieBuddy version running in the game.

Source: ZombieBuddy · author Workshop instructions · Framework author instructions

Understand the 42.21 fix before adding a patch

The official v2.3.4 release, dated 3 October 2026, backports fix #56. Begin with the author’s current release when resolving an old 42.21 setup. A tutorial recorded before that release may still recommend a temporary community JAR.

Check what the game actually loaded after an update. A newly downloaded file elsewhere on disk is not proof that the active game directory uses it. Preserve the previous configuration while replacing an older or temporary setup with a consistent author release.

Source: ZombieBuddy v2.3.4 · release · Framework author release

Prepare the game and paths

1. Close Project Zomboid and back up any save you will use. Confirm that the game can reach its menu without this loader before changing the installation.
2. Use Steam’s installed-files browse action to locate the actual game folder. A library on another drive will not match an example beginning with C:\Program Files (x86).
3. Copy your current Steam launch options to a note. If editing a launcher JSON or BAT file, preserve an unchanged copy and record the exact file you changed.
4. Let the Workshop dependency finish downloading, or use the author’s release package. Keep a record of which source supplied the files; avoid parallel local and Workshop copies whose versions you cannot distinguish.

Windows: use the author installer

If the downloaded installer does not offer the documented choices, check its own release notes and use the matching manual route below. Do not assume that an installer reaching its last screen means it patched the launcher you later selected.

1. Subscribe to the author’s ZombieBuddy Workshop item, then download ZombieBuddyInstaller.exe from the author’s GitHub Releases.
2. Run the installer and choose installation/update. The documentation offers Normal Launch, Alternate Launch or Both; select the launch method you actually use.
3. Inspect the detected folders and change preview. If asked to close Steam for a launch-options change, do so and continue.
4. After completion, enable ZombieBuddy in the game mod manager and fully restart. Check the loading indicator before adding a dependent mod.

Source: ZombieBuddy v2.3.4 · installation guide · Versioned author documentation

Windows: manual file placement

Copy ZombieBuddy.jar and zbNative.dll from the downloaded mod’s libs directory into the game installation directory. The Workshop example below is relative to the Steam library containing that download, not necessarily your system drive.

SOURCE: <Steam library>\steamapps\workshop\content\108600\3619862853\mods\ZombieBuddy\libs\
FILES: ZombieBuddy.jar and zbNative.dll
DESTINATION: the ProjectZomboid game folder opened through Steam

Source: ZombieBuddy · author Workshop instructions · Framework author instructions

Windows: configure Normal Launch

For the manual Steam Normal Launch route, use the following agent argument, including the final two hyphens. zbNative loads the JAR; adding a second javaagent argument is unnecessary. Preserve unrelated options and compare any existing ZombieBuddy entry before adding another.

-agentlib:zbNative --

Source: ZombieBuddy v2.3.4 · installation guide · Versioned author documentation

Windows Alternate Launch uses a different injection point

The author instructions explain that Steam arguments reach ProjectZomboid64.bat as game arguments. The Normal Launch line alone therefore does not set up Alternate Launch. Use the installer’s Alternate Launch/Both option, or add -agentlib:zbNative to that BAT file’s SET _JAVA_OPTIONS= line.

For a manual edit, first inspect the existing line and preserve its other JVM options. Do not replace the entire launcher with a snippet from a comment. If you cannot identify the correct line, return to the documented installer instead of guessing.

Source: ZombieBuddy v2.3.4 · installation guide · Versioned author documentation

Native macOS and Linux: copy the JAR and set the agent

A Steam Deck running the Windows game through Proton is a different launch configuration from the native Linux example. Identify which game executable is in use before selecting a platform recipe; this page does not claim a tested Proton or Steam Deck setup.

-javaagent:ZombieBuddy.jar --

Source: ZombieBuddy · author Workshop instructions · Framework author instructions

Verify the loader before testing a dependent mod

During loading, the author documents a ZombieBuddy icon and version message at the upper left. Note the number that actually appears.

1. First confirm that the game reaches its menu with the configured loader. If it cannot, undo the loader changes and compare with the baseline before investigating a camera or gameplay addon.
2. Next enable only the intended dependent mod and its stated requirements in a separate test setup. Restart fully.
3. Read any approval prompt, then test one visible feature of that mod. A loader indicator alone does not establish that another mod started successfully.
4. Record both results separately: framework reached the menu, and dependent mod performed its intended action. Keep any failure message verbatim.

Source: ZombieBuddy v2.3.4 · installation guide · Versioned author documentation

Approve a file deliberately and fix an accidental denial

The author documents approval of new or changed Java JARs and stored per-file decisions. For an accidental denial, close the game, back up mod_approvals.json, and revise only the intended mod/hash entry under mods before restarting. The default file is %USERPROFILE%\.zombie_buddy\mod_approvals.json on Windows, or ~/.zombie_buddy/mod_approvals.json on native macOS/Linux.

Compare the displayed file with the mod you requested. Avoid clearing all decisions merely because one addon was blocked; that loses information about unrelated choices.

Source: ZombieBuddy · author Workshop instructions · Framework author instructions

Understand policy and signature messages

The documented prompt policy asks about unfamiliar or changed JARs; deny-new can skip unapproved files without showing a dialog. Inspect an existing policy argument if a new dependency seems to disappear. Keep deliberate restrictions in place while identifying the reason for the block.

Do not use allow-all as a troubleshooting shortcut. If the message names a signature or author key, diagnose that specific issue rather than treating it as a generic permission dialog.

Source: ZombieBuddy v2.3.4 · agent parameters · Versioned author reference

Does a valid signature mean the mod is safe?

No. The author describes signing as an identity and integrity check, not a security review. Java mods can execute code with your account’s system access; choose the source and approve the specific mod accordingly.

For mismatched signature files, obtain a consistent JAR and its accompanying signature from the author. Replacing only one file, using a repack or mixing releases can invalidate the relationship. If verification still fails, retain the error and ask the author about that version instead of bypassing the check.

Source: ZombieBuddy v2.3.4 · mod signing · Versioned author documentation

Troubleshoot not installed, no mods loaded or startup failure

The upstream 42.21 report explains a changed Java method signature that stopped the loader matching its hook. It is one documented failure mode, not a diagnosis for every startup crash.

Source: ZombieBuddy #56 · Build 42.21 loading fix · Upstream fix discussion

Collect a useful diagnostic log

If the ordinary launch gives too little information, the author supports verbosity=1. For Windows Normal Launch, replace the existing agent argument with the example below for one diagnostic run, preserve the output and return to your previous setting afterward. Alternate Launch still needs its own JVM injection point.

Report the first error, exact patch and loader version, installation source, launch mode and smallest failing mod list. Remove private account paths or server details before sharing logs.

-agentlib:zbNative=verbosity=1 --

Source: ZombieBuddy v2.3.4 · agent parameters · Versioned author reference

Native macOS/Linux diagnostic argument

-javaagent:ZombieBuddy.jar=verbosity=1 --

Source: ZombieBuddy v2.3.4 · agent parameters · Versioned author reference

Uninstall without leaving a broken launcher

Preserve unrelated launch options and configuration. Uninstalling the loader does not prove that effects from every previously installed dependent mod have been reversed in a save.

1. Close the game. Disable dependent Java mods in the test setup. If your installer offers Uninstall ZombieBuddy, use it and inspect its change preview.
2. For manual removal, undo the ZombieBuddy agent argument in Steam. If you also patched ProjectZomboid64.json or ProjectZomboid64.bat, restore those specific edits from your recorded configuration before removing the files they load.
3. Remove ZombieBuddy.jar and any ZombieBuddy.jar.new from the game directory. On Windows also remove zbNative.dll. Unsubscribe/remove the mod package if you no longer need it.
4. Keep the .zombie_buddy config folder unless you intentionally want to discard approval decisions and caches. Removing that optional folder is not required just to stop the agent.
5. Launch through each method you changed and confirm that the ordinary game reaches its menu without a loader-file error. Check a separate baseline world before reopening the save you care about.

Source: ZombieBuddy · uninstall guide · Current author removal instructions

Do you need a separate Java or Gradle installation?

Do not replace the game’s bundled runtime merely to reconcile a README line. The reviewed development README mentions Java 25, while the v2.3.4 README mentions Java 17; the end-user installation instructions focus on the game installation and agent files. Gradle is listed for building Java mods.

For a runtime error, identify the actual game patch, launcher and release first, then follow the author’s matching instructions. Compiling the framework from the development branch is outside this end-user setup guide.

Source: ZombieBuddy v2.3.4 · README · Versioned author documentation