Moon Sweepers crashes and launch errors: what to try

Which problem are you seeing?

Moon Sweepers has several distinct failures, and they do not share a fix. Start with the symptom rather than the settings.

Crash behaviour varies enormously between machines: several crashes an hour in a world with almost nothing built on some systems, none across a 35-hour playthrough on others.

What should you try first?

1. Update to 1.0.5. It fixes memory leaks and a freeze that hit worlds shortly after loading, on both DirectX 11 and DirectX 12. See the patch notes.
2. Verify the installed files in Steam: right-click the game, open Properties, then Installed Files → Verify integrity of game files.
3. Test the other DirectX option, using the launch-option steps below.
4. Lower the graphics load for one session — quality preset, motion blur off — to see whether the crash follows the setting.
5. Turn off overlays while testing. Overlay hooks from Steam, Discord and GPU driver software are worth ruling out, and they are quick to switch back on.

If a crash repeats at the same action, note what you were doing: placing or deleting a piece, driving a vehicle, selling at a station, or opening the map.

Does DirectX 12 cause the crashes?

Since patch 1.0.4, Windows PCs with AMD GPUs default to DirectX 11 to prevent crashes. Adding -force-d3d12 to the game’s Steam launch options opts back into DirectX 12. If you added that flag earlier and the game has become unstable, remove it and test the default again.

To change the option: Steam Library → right-click Moon Sweepers → Properties → General → Launch Options.

Some players still crash on DirectX 11. Keep the argument you end up with written down; a later patch may change which default suits your card. The system requirements page covers the AMD default and the full specs table.

Why does the game crash when you alt-tab?

Returning to the game at 4K in fullscreen is the most consistent report: the game hangs or closes when it comes back to the foreground, and in some cases the audio keeps playing while the window will not return.

Try, in order: borderless or windowed mode, a lower resolution, then the other DirectX option. Players who moved off 4K fullscreen stopped hitting it.

Why does the game stutter when the base grows?

Late-game slowdown is a load problem rather than a crash, and the reported causes are volume, not graphics settings. Players describe frame drops with hundreds of J.O.O.N.A.S. robots, with very long belts holding thousands of capsules, and around heavily built industrial areas — often with the GPU and CPU both sitting well below full load.

Practical steps:

• Stop buying robots once cleaning is nearly finished. Several players trace the worst stutter to fleets of several hundred; one stopped at 400 robots.
• Remove machines and long belt runs you no longer need, especially belts parked full of capsules with no output.
• Keep outputs flowing so capsules do not accumulate in the network. An unconnected Capsule Catcher drains incoming capsules instead of letting them queue on belts.
• Lower settings if the drop appears while driving or looking across the base.

One lane moves about 88 capsules a minute, so a factory that outgrows its output lane backs capsules up along the belt until a parallel lane is added or production drops. The conveyor belt reference covers lane capacity and splitting.

DragDrop Games lists continued optimization for larger bases among the planned Update 1.1 work in December 2026; the 1.1 preview covers the rest.

What if a co-op client stops seeing cleaned ground?

A joining player can lose the streamed map detail: the ground falls back to a low-detail view, dust cannot be vacuumed, and hexes read 0.0% until the session is reloaded. Cleaning progress is shared, so the host still sees the correct ground; the joining player’s map is what stops updating.

Disconnect and rejoin the host’s world. If it returns every few hundred metres, stop the trip and report it with your version, whether you hosted, and roughly how far you travelled. The multiplayer guide covers version matching and lobby rules.

What should you include in a bug report?

Send crashes to DragDrop Games through their official Discord rather than a Steam reply chain. Useful details:

Include the last few things you did rather than only the error text. For worlds that will not open, freezes, or Save Unavailable, the save guide has the backup folder and repair behaviour.

Game imagery © DragDrop Games.