Godot 4.5 C# Hot Reload Not Working - .NET SDK and Editor Integration Fix

If C# changes in Godot 4.5 only apply after a full editor restart, your iteration loop slows down fast. In most cases, hot reload is not truly broken by your gameplay code. It is broken by SDK mismatch, stale restore artifacts, or editor integration drift.

This guide gives a stable fix path you can run in 10-20 minutes.

Problem summary

Common symptoms:

C# scripts compile, but scene behavior does not update until restart.
Godot reports successful build while old logic is still running.
First reload works once, then silently stops in longer sessions.

Typical impact:

False bug reports because old code keeps executing.
Slow QA loops and duplicate restart-only workarounds in the team.

Why this happens

Hot reload depends on three pieces staying aligned:

Godot 4.5 editor C# integration state
Correct .NET SDK/runtime selected on your machine
Clean project restore/build artifacts for the current branch

If one drifts, compile can appear green while runtime assembly reload fails.

Step-by-step fix

Step 1 - Confirm SDK version actually used by the project

From your project root, verify which SDK is selected by global.json or fallback resolution.

If your team pins SDK versions, install and use the same one.
If no version pin exists, align to the SDK range your Godot 4.5 C# setup expects.

Mismatched SDK versions are a frequent cause of partial compile or inconsistent reload behavior across machines.

Step 2 - Rebuild C# project files from inside Godot

In Godot:

Open the C# project.
Regenerate or refresh project solution files.
Trigger a clean build from the editor integration path (not only external IDE).

This ensures Godot and your IDE point at the same generated project metadata.

Step 3 - Clear stale restore and temp outputs

Close Godot and your IDE, then clear stale artifacts used by C# compilation for this project (for example intermediate bin or obj output folders in your C# project paths). Reopen and restore/build again.

This removes old assembly output that can cause "build succeeded, runtime unchanged" behavior.

Step 4 - Verify editor and IDE integration settings

Check:

external editor path is valid
correct solution is being opened (no duplicate parent-folder solution)
file watcher integration is enabled and not blocked by antivirus or sync conflicts

In multi-root setups, make sure you are editing the same project folder Godot opened.

Step 5 - Run a hot reload smoke test

Use a tiny deterministic script test:

Change one debug string or counter increment.
Build in editor.
Re-enter the same scene path.
Confirm behavior change appears without full restart.

Repeat twice. One successful reload is not enough; intermittent reload failure is common when artifacts are stale.

Verification checklist

Script edits apply without restarting Godot.
Build output remains consistent across two consecutive reload attempts.
Team members on the same branch reproduce the same reload behavior.

Alternative fixes

If only one machine fails, reinstall the exact SDK and regenerate solution files.
If only CI or shared runners fail, compare environment SDK pinning against local machines.
If issue appears after branch switches, rerun restore + clean output removal before debugging gameplay code.

Prevention tips

Keep SDK pinning explicit in project docs to avoid silent machine drift.
Add a short "C# reload smoke test" to branch-upgrade checklists.
Avoid editing through duplicate workspace roots for the same Godot project.