Mod isn't loading

1. Is IPA still applied? A Steam update can un-patch the game. Re-drag JetIsland.exe onto IPA.exe (§2.2.3).
2. Is the .dll in Plugins\? Not in a subfolder, not still zipped.
3. Check the log. Open JetIsland_Data\output_log.txt (or the Unity Player log). Look for IPA loading your plugin and for any exception thrown from your Name/Version getters or OnApplicationStart. A plugin that throws during load gets skipped.
4. Wrong target framework / Unity mismatch. If the DLL was built against the wrong .NET profile or a different Unity, it may fail to load silently. Rebuild against the game's Managed\ assemblies with a classic .NET Framework target.
5. Used the wrong IPA. Make sure it's the patched IPA-3.4.1-ca30be3 build, not a random upstream IPA.

AssetBundle won't load

• Unity version mismatch is the #1 cause — rebuild the bundle in 2017.1.1.
• Wrong path. Confirm the .unity3d is where your plugin expects (usually JetIsland_Data\StreamingAssets\) and that the asset name in LoadAsset<T>("name") matches exactly.
• Wrong build target. Build for StandaloneWindows64.

Game won't launch at all after installing mods

• Remove the last mod you added from Plugins\ and try again — a single bad plugin can take the game down.
• If still broken, Alt-drag JetIsland.exe onto IPA.exe to fully un-patch and confirm vanilla launches. Then re-apply IPA and add mods back one at a time to find the culprit.
• Verify game files (Steam: Properties → Installed Files → Verify integrity) if you suspect the install itself is damaged.

Compatibility with game updates

This is the big one for an older game whose mod catalog has historically gone long stretches without updates:

• A game update can break a mod if it changes a method or field a mod hooks. Symptoms: the mod silently does nothing, or the game throws on load.
• Patch mods are most fragile (they depend on specific game internals); pure-asset map mods are usually more robust.
• As an author: re-test after each game update, bump the PATCH version with the fix, and note the tested game version (§6).
• As a player: if a mod broke after an update, check the mod's page for a newer build, and report the break to the author (Discord #modding). Removing the mod's .dll always restores the game.

Keep your runtime patched

Unrelated to a specific mod: keep your game's Unity runtime current via the platform. (Unity disclosed a runtime-level vulnerability, CVE-2025-59489, affecting games built with Unity 2017.1+, mitigated by Steam client updates and patched runtimes.) Only install mods from this site or other reputable sources, and prefer open-source mods you can read.