Fixing the Things That Break

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Before anything else: check your game version. Moon Sweepers received 1.0.3 and 1.0.4 within two days of launch, and several common problems — dust reappearing, machines refusing to pack capsules, saves that looked corrupted — were fixed in those patches.

Crashes and startup

The game will not launch

1. Verify the game files in Steam.
2. Update your graphics driver.
3. If you are on an AMD card, do not force DirectX 12 — 1.0.4 made DX11 the default specifically to prevent AMD crashes.
4. On Linux or Steam Deck, try a newer Proton version; 1.0.4 fixed startup on older ones.

It crashes mid-session, usually on a big base

Large automated bases are the demanding case. The developers acknowledged remaining crash reports after 1.0.4. Reduce the number of simultaneously active robots and machines as a test — if stability improves, you are hitting a load issue rather than a specific bug.

Low frame rate

Patch 1.0.3 claimed roughly 20% higher frame rates on large bases in the developers' tests, so if you are on the launch build, update first.

If it is still slow, the cost is almost always one of these:

• Robot count. Many active machines update continuously. Pause or remove ones covering already-clean ground.
• Base size. Foundations and buildings spanning many tiles add geometry.
• Conveyor length. Very long routes with many mergers move a lot of capsules.
• Ground loading. Driving fast across unexplored terrain causes stutter; 1.0.3 reduced this but did not eliminate it.

Multiplayer

Someone cannot join

1. Confirm both players are on the same version — this is stated in the 1.0.3 notes.
2. Confirm the host is in an actual co-op session, not a solo save.
3. Check the crew menu in the ESC screen — the player may have been banned from that save.
4. Restart Steam if the session is not appearing at all.

Cleaned ground reappears for some players

This was a real bug fixed in 1.0.4, which reworked ground synchronisation so everyone sees the same cleaned ground including robot trails. If it still happens, someone is on an older build.

A crewmate cannot edit a belt

Fixed progressively: 1.0.3 made crewmate-built splitters and mergers work, and 1.0.4 allowed any crewmate to place splitters and mergers on belts another player built.

Upgrades are not showing for other players

Since 1.0.3 the whole crew uses the host's upgrade matrix and anyone's purchase upgrades everyone. If a crewmate is missing an upgrade, check they are actually connected to the current session rather than a rejoin in progress.

Conveyors and machines

The belt direction test

Follow one capsule with your eyes from the source to the depot. Watch it at every join, including the first one. A belt that looks continuous can have a single reversed segment, and that segment behaves exactly like a wall.

Power problems

A single Pressure Chamber needs more than three basic Solar Posts to run on solar alone. A Pressure Chamber plus a Stone Press needs 28 kW before other equipment.

Check the network's stored charge, not just the number of panels. A system with ample nominal generation can still halt at night if the battery cannot carry the load.

J.O.O.N.A.S. issues

Most J.O.O.N.A.S. complaints predate 1.0.4, which substantially rewrote its behaviour.

• It no longer needs to return to a dock — it fires capsules to the nearest Capsule Catcher while moving.
• It keeps working when no players are nearby.
• It skips hexes it cannot reach instead of circling them.
• Its bin gauge flashes red when full.

If it still stops, check that a Capsule Catcher exists and that the catcher's output actually connects to your network. A catcher with a blocked output is the same as no catcher.

Saves and recovery

Since 1.0.4 the game keeps up to five backups per save slot, taken a minute into each session and then every 30 minutes, stored outside Steam Cloud:

C:\Users\<you>\AppData\LocalLow\DragDropGames\MoonSweepers\Backups

Damaged saves are repaired automatically when they load, and after a crash the game checks save files on the next start.

Controller and Steam Deck

Steam lists full controller support including DualShock, DualSense and Steam Input, so gamepads work throughout. If a controller is not detected, check Steam Input is enabled for the game.

On Steam Deck, compatibility is listed as Unknown rather than verified. Patch 1.0.4 fixed startup issues on older Proton versions, so try a recent Proton build before concluding it does not work.

Still stuck? The official Discord is where the developers collect bug reports — it is linked from the Steam page. For the machinery side of things, the automation guide covers correct wiring in detail.