Find the addon behind a Garry’s Mod Lua error

~~CloudExa~~A ~~help~~Lua ~~guide.~~error is a clue about a failed script, not a reason to erase the server. It may affect one menu or prevent an entire gamemode from initializing. Your aim is to reproduce the fault, identify the first failing component and test a reversible change.

Capture the first error

Save the full error block, including its file path, line number and stack trace. Record what happened immediately beforehand: startup, player join, a weapon action or a menu click. Note the active map, gamemode and recently changed addons.

Read earlier messages too. A later nil-value error may only be the consequence of a dependency that failed first. Keeping just the last line can send the investigation toward the wrong addon. Redact player details, database credentials, webhook URLs and tokens before posting logs publicly.

Find the relevant Lua realm

Garry's Mod has separate server, client and menu Lua contexts. A client-side function is not automatically available to a server script. Use the error's source and the location where it appears to decide which log you need. The dedicated console cannot show every local client failure.

Ask an affected player for their complete client error if the symptom is a broken HUD or menu. Compare with another consenting test player. If only one person is affected, investigate their addon set and downloaded content before changing the whole community's server configuration.

Read the trace without guessing a code fix

A file path under a named addon provides a starting point, but that addon may rely on another library.
A nil function or value can mean a missing dependency, wrong initialization order or an outdated API.
A syntax error after a configuration edit often points to a missing quote, bracket or separator near the reported location.
A missing include can mean an incorrect path, filename case or incomplete package.

Do not rename functions or suppress the error message simply to make the console quiet. That can conceal a broken economy, permission system or persistence feature. Compare with the author's supported release and configuration format instead.

Isolate safely

Back up configuration, garrysmod/data/ and any addon database before testing. Use a separate test service where possible. Otherwise arrange maintenance, stop normally and save a copy of the current collection and local addon list.

Start with the most recent optional addon change and its documented dependencies. Disable a local addon reversibly by moving its folder outside the active garrysmod/addons/ tree, retaining the original path in your notes. For Workshop content, use a temporary test collection. Do not delete persistent data or remove a required gamemode framework mid-test.

If many optional addons are involved, test groups, narrowing the failing group each time. Keep a known working dependency set. Restore the previous selection after each unsuccessful hypothesis rather than accumulating unrelated changes.

Confirm and report

Repeat the exact triggering action after the correction. Check both client and server output, then verify persistence through a controlled restart. Send the addon author a minimal reproduction, versions and redacted trace if a supported combination still fails. Keep the backup until normal gameplay and saved data have both been confirmed.