What causes Godot not restoring the window mode on restart?

You set the window mode at runtime but never saved it, so each launch falls back to the project setting's default mode rather than the player's last selection.

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 Godot Not Remembering Fullscreen or Windowed on Restart

Quick answer: Persist the chosen window mode to a config file and reapply it on startup with DisplayServer.window_set_mode before the first frame.

A player sets the game to fullscreen, quits, and reopens it windowed every time. The mode was applied but not saved. Store it and reapply it at boot.

How to fix it

1. Save the mode

When the player changes window mode, write the value to a ConfigFile (or your settings resource). Do not rely on the project's default window settings to remember a runtime choice.

2. Reapply early at boot

On startup, read the saved mode and call DisplayServer.window_set_mode(...) in an autoload's _ready before gameplay, so the first frame is in the right mode.

3. Persist size too

Also save window size and position for windowed mode, and clamp them to the current screen so a saved off-screen window does not appear lost.

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.

Reproduce it once with full context and the fix writes itself. The hunt is the expensive part.