What causes .NET assembly errors when running an exported Godot C# game?

The C# solution was not built for the export or the export lacks the .NET assemblies — exporting without a successful dotnet build, missing export templates for the .NET variant, or mismatched SDK versions.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix a Godot C# Project Failing With “.NET assemblies not found” on Export

Quick answer: Build the C# solution for the target, use the .NET edition's matching export templates, and verify the exported folder contains the game's assemblies next to the executable.

The .NET edition of Godot ships your game's C# as assemblies alongside the pack; when the export misses or mismatches them, the game dies at startup with this. Here is the reliable export path.

How to fix it

1. Build before exporting

Ensure dotnet build succeeds for the project (the editor does this on export, but its errors scroll by) — a failed build exports a game with stale or missing assemblies.

2. Use the .NET export templates

The .NET (Mono) editor needs its own template package matching the exact engine version; standard templates on the .NET editor produce broken exports.

3. Match the SDK

Install a .NET SDK version compatible with your Godot release on every machine that exports, CI included — version drift breaks reproducibility.

4. Inspect the export output

Confirm the exported folder (or embedded pck layout) includes YourGame.dll and companions; a quick launch of the export on a clean machine is the honest test.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every Godot error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

Most of the time the fix is small. Seeing the failure clearly is the part that actually costs you.