2026.11.12.01

For the normal game (U59). Playing the U60 public test (Steam beta public_testing)? Use the latest U60 build instead.

New

• Super-sized screenshots (the debug screenshot's larger sizes) come out as one seamless image at any size, without the UI.

Faster

• Loading a save is quicker: the game no longer waits for its shaders to compile before it carries on loading (about 1.4 s on Linux).
• Snapshots, colony previews and screenshots save faster, and their PNG files are about 20–25% smaller. A very large screenshot takes far less memory while it is being saved.
• Busy menus and screens draw far more efficiently. The Load screen with many saves draws its colony list in about 80 draw calls instead of about 7,200.
• Less memory churn every frame, so garbage collections are fewer and shorter.

Fixes

• With mods such as Fast Track and Better Info Cards on Windows, clicking a tile repeatedly cycles through everything on it from the first click after loading, as in the original. Before, it only started working after 10–20 seconds of clicking. The same fix makes other mods' patches on this kind of game method work from the start. Reported in #52 by @isochronous.
• On Windows, buildings, plants and critters no longer brighten and darken while Beakons or other moving lights are on screen. Their lighting now matches the original on Direct3D 11. Reported in #76 by @isochronous.
• Taking a large super-sized screenshot (Alt+3 at the bigger sizes) no longer crashes the game. Reported in #75 by @isochronous.
• Fewer sound crashes ("0xC0000374 (heap corruption)") on long sessions with busy colonies:
  • Forget released sounds (Moono Tweaks, on by default): the game kept using sounds it had already released. After a few hours on a busy colony those could point at other sounds and corrupt memory.
  • Stolen sound crash guard (Moono Tweaks, on by default): fixes a bug in FMOD, the game's sound library, that wrote to a sound it had just freed when many sounds played at once.
  • Sound memory guard (Moono Tweaks, on by default, Windows): FMOD's memory is now laid out so that a stray write can no longer corrupt the heap.
  • Reported in #78 by @yewuxin, #72 by @sbwcwso, and #58 and #73 by @charmich0802.
• Correct daily colony snapshots (Moono Tweaks, on by default): colony snapshots saved each cycle no longer get vertical stripes, squeezed lights or stray effects.
• Crash logs say more: a fast-fail crash (0xC0000409) names the module it happened in, and an out-of-memory error logs where it happened and how much memory was in use.

Built by GitHub Actions from commit 0fd22a2 (build) and attested. How to verify a download.

Install or update: download the archive for your system and extract it.

• Windows: double-click oni-moono\player\OniMoono.exe to play, or run setup.cmd once to start Moono from Steam's Play button instead.
• Linux: double-click oni-moono/oni-moono.desktop to play (your file manager may ask to allow launching it once), or run ./setup.sh once to start Moono from Steam's Play button instead.

If you already set it up, running the new setup is enough.

2026.11.12.02 (U60 Beta)

Only for Oxygen Not Included's U60 public test (game build 762230, Steam beta public_testing). On the normal game, use the latest normal release. If this build is started on the wrong game version, it says which build to get instead of crashing.

An update to the U60 beta, built from the u60 branch.

New

• Super-sized screenshots (the debug screenshot's larger sizes) come out as one seamless image at any size, without the UI.

Faster

• Loading a save is quicker on OpenGL: the game no longer waits for its shaders to compile before it carries on loading (about 1.4 s on Linux).
• Snapshots, colony previews and screenshots save faster, and their PNG files are about 20–25% smaller. A very large screenshot takes far less memory while it is being saved.
• Snapshots and save previews no longer pause the game, and the first snapshot and the first Spaced Out preview after loading are faster than the original's.
• Faster pipe network rebuilds (Moono Tweaks, on by default): building or removing pipes no longer makes every pipe in the colony recheck its network. About 20–25 ms less a rebuild on a 27,000-pipe colony, and far less after mass deconstruction.
• Busy menus and screens draw far more efficiently. The Load screen with many saves draws its colony list in about 80 draw calls instead of about 7,200.
• Less memory churn every frame, so garbage collections are fewer and shorter.

Fixes

• With mods such as Fast Track and Better Info Cards on Windows, clicking a tile repeatedly cycles through everything on it from the first click after loading, as in the original. Before, it only started working after 10–20 seconds of clicking. The same fix makes other mods' patches on this kind of game method work from the start. Reported in #52 by @isochronous.
• On Windows, buildings, plants and critters no longer brighten and darken while Beakons or other moving lights are on screen. Their lighting now matches the original on Direct3D 11. Reported in #76 by @isochronous.
• Taking a large super-sized screenshot (Alt+3 at the bigger sizes) no longer crashes the game. Reported in #75 by @isochronous.
• Fewer sound crashes ("0xC0000374 (heap corruption)") on long sessions with busy colonies:
  • Forget released sounds (Moono Tweaks, on by default): the game kept using sounds it had already released. After a few hours on a busy colony those could point at other sounds and corrupt memory.
  • Stolen sound crash guard (Moono Tweaks, on by default): fixes a bug in FMOD, the game's sound library, that wrote to a sound it had just freed when many sounds played at once.
  • Sound memory guard (Moono Tweaks, on by default, Windows): FMOD's memory is now laid out so that a stray write can no longer corrupt the heap.
  • Reported in #78 by @yewuxin, #72 by @sbwcwso, and #58 and #73 by @charmich0802.
• Correct daily colony snapshots (Moono Tweaks, on by default): colony snapshots saved each cycle no longer get vertical stripes, squeezed lights or stray effects.
• The Load screen and Retired Colonies no longer read a colony image that is still being written, a bug in U60 itself.
• Crash logs say more: a fast-fail crash (0xC0000409) names the module it happened in, and an out-of-memory error logs where it happened and how much memory was in use.

Built by GitHub Actions from commit b94eec0 (build) and attested. How to verify a download.

Install or update: download the archive for your system and extract it.

• Windows: double-click oni-moono\player\OniMoono.exe to play, or run setup.cmd once to start Moono from Steam's Play button instead.
• Linux: double-click oni-moono/oni-moono.desktop to play (your file manager may ask to allow launching it once), or run ./setup.sh once to start Moono from Steam's Play button instead.

If you already set it up, running the new setup is enough.

2026.11.10.05

For the normal game (U59). Playing the U60 public test (Steam beta public_testing)? Use the latest U60 build instead.

Fixes

• Steam starts and owned DLCs are detected, including the Spaced Out toggle, even when another program left an older steam_api64.dll on the PC. Moono now loads the game's plugins from the game's folder, as in the original. Reported in #74 by @Pafik34V.
• Sound memory guard (Moono Tweaks, on by default, Windows): works around a crash in FMOD, the game's sound library ("0xC0000374 (heap corruption)"), seen on large colonies. FMOD now gets a separate memory heap that holds freed memory back before reusing it. If FMOD writes to memory it already freed, the write lands there harmlessly and Player.log gets an fmod heap: line. Uses about 50 MB more memory on a large colony. Reported in #72 by @sbwcwso, and in #58 and #73 by @charmich0802.

Built by GitHub Actions from commit 2864d5e (build) and attested. How to verify a download.

Install or update: download the archive for your system and extract it.

• Windows: double-click oni-moono\player\OniMoono.exe to play, or run setup.cmd once to start Moono from Steam's Play button instead.
• Linux: double-click oni-moono/oni-moono.desktop to play (your file manager may ask to allow launching it once), or run ./setup.sh once to start Moono from Steam's Play button instead.

If you already set it up, running the new setup is enough.

2026.11.10.03

For the normal game (U59). Playing the U60 public test (Steam beta public_testing)? Use the latest U60 build instead.

New

• Linux: double-click oni-moono.desktop in the extracted folder to play. setup.sh also offers to add Moono to the applications menu.
• Linux: started from the launcher or a file manager, Moono shows its messages in a desktop dialog, such as why it couldn't start or which game install to use. Before, they went only to a terminal nobody saw.

Faster

• Compact report history (Moono Tweaks, on by default): past days' reports take far less memory: about 1.4 GB less in use on a late-game colony, and it loads about 1 s faster.
• Share identical data (Moono Tweaks, on by default): Duplicants' names in every day's report and other identical data are kept once, about 0.3 GB less memory on a late-game colony.
• Popup texts, copied objects and image effects allocate less memory while playing, so garbage collections come less often.

Fixes

• The temperature overlay shows the temperature in cells open to space, such as a rocket's exhaust, as in the original. On NVIDIA's Windows driver those cells showed the stars. Reported in #71 by @RoaringFlame.

Built by GitHub Actions from commit 9528e5e (build) and attested. How to verify a download.

Install or update: download the archive for your system and extract it.

• Windows: double-click oni-moono\player\OniMoono.exe to play, or run setup.cmd once to start Moono from Steam's Play button instead.
• Linux: double-click oni-moono/oni-moono.desktop to play (your file manager may ask to allow launching it once), or run ./setup.sh once to start Moono from Steam's Play button instead.

If you already set it up, running the new setup is enough.

2026.11.10.06 (U60 Beta)

Only for Oxygen Not Included's U60 public test (game build 762230, Steam beta public_testing). On the normal game, use the latest normal release. If this build is started on the wrong game version, it says which build to get instead of crashing.

An update to the U60 beta, built from the u60 branch.

Fixes

• Steam starts and owned DLCs are detected, including the Spaced Out toggle, even when another program left an older steam_api64.dll on the PC. Moono now loads the game's plugins from the game's folder, as in the original. Reported in #74 by @Pafik34V.
• Sound memory guard (Moono Tweaks, on by default, Windows): works around a crash in FMOD, the game's sound library ("0xC0000374 (heap corruption)"), seen on large colonies. FMOD now gets a separate memory heap that holds freed memory back before reusing it. If FMOD writes to memory it already freed, the write lands there harmlessly and Player.log gets an fmod heap: line. Uses about 50 MB more memory on a large colony. Reported in #72 by @sbwcwso, and in #58 and #73 by @charmich0802.

Built by GitHub Actions from commit 4e42296 (build) and attested. How to verify a download.

Install or update: download the archive for your system and extract it.

• Windows: double-click oni-moono\player\OniMoono.exe to play, or run setup.cmd once to start Moono from Steam's Play button instead.
• Linux: double-click oni-moono/oni-moono.desktop to play (your file manager may ask to allow launching it once), or run ./setup.sh once to start Moono from Steam's Play button instead.

If you already set it up, running the new setup is enough.

2026.11.10.04 (U60 Beta)

Only for Oxygen Not Included's U60 public test (game build 762230, Steam beta public_testing). On the normal game, use the latest normal release. If this build is started on the wrong game version, it says which build to get instead of crashing.

An update to the U60 beta, built from the u60 branch.

New

• Linux: double-click oni-moono.desktop in the extracted folder to play. setup.sh also offers to add Moono to the applications menu.
• Linux: started from the launcher or a file manager, Moono shows its messages in a desktop dialog, such as why it couldn't start or which game install to use. Before, they went only to a terminal nobody saw.

Faster

• Compact report history (Moono Tweaks, on by default): past days' reports take far less memory: about 1.4 GB less in use on a late-game colony, and it loads about 1 s faster.
• Share identical data (Moono Tweaks, on by default): Duplicants' names in every day's report and other identical data are kept once, about 0.3 GB less memory on a late-game colony.
• Popup texts, copied objects and image effects allocate less memory while playing, so garbage collections come less often.

Fixes

• With OpenGL, the temperature overlay shows the temperature in cells open to space, such as a rocket's exhaust, as in the original. On NVIDIA's Windows driver those cells showed the stars. With Vulkan it already worked. Reported in #71 by @RoaringFlame.

Built by GitHub Actions from commit 9e3611b (build) and attested. How to verify a download.

Install or update: download the archive for your system and extract it.

• Windows: double-click oni-moono\player\OniMoono.exe to play, or run setup.cmd once to start Moono from Steam's Play button instead.
• Linux: double-click oni-moono/oni-moono.desktop to play (your file manager may ask to allow launching it once), or run ./setup.sh once to start Moono from Steam's Play button instead.

If you already set it up, running the new setup is enough.

2026.11.10.01

For the normal game (U59). Playing the U60 public test (Steam beta public_testing)? Use the latest U60 build instead.

New

• Exact worldgen (Moono Tweaks, on by default): a seed now makes the same map as in the original game. Worldgen ran the same steps but rounded floating-point math slightly differently, which shifted biome borders and abyssalite. Reported in #66 by @Tenzian.

Faster

• The engine allocates about another third less memory per frame on a late-game colony, so garbage collections come less often.

Fixes

• Saves with a care package that hadn't opened yet failed to load and crashed shortly after. They now load as in the original. Reported in #69 by @Estenee.
• Updating mods from the main menu with Mod Manager no longer freezes the game until Windows closes it. Reported in #65 by @braziliancara.
• The RivaTuner / MSI Afterburner overlay shows again. Reported in #64 by @hao7259.
• Hover cards lay out text that changed this frame at its new width, as in the original. Mods that measure hover text (such as Thermal Tooltips Reworked) line up again. Reported in #70 by @NsPro04.
• On high-DPI screens the mouse pointer is the same size as in the original. It was smaller at 150% and 200% scaling. Reported in #62 by @Crazyboy233.
• When a coroutine throws, Klei's error dialog and the log show the same stack trace as in the original, not Moono's internals.
• The crash window names a hang ("ended by Windows as not responding") instead of only showing its code.

Built by GitHub Actions from commit 93cfa55 (build) and attested. How to verify a download.

Install or update: download the archive for your system and extract it.

• Windows: double-click oni-moono\player\OniMoono.exe to play, or run setup.cmd once to start Moono from Steam's Play button instead.
• Linux: run ./setup.sh in the oni-moono folder.

If you already set it up, running the new setup is enough.

2026.11.10.02 (U60 Beta)

Only for Oxygen Not Included's U60 public test (game build 762230, Steam beta public_testing). On the normal game, use the latest normal release. If this build is started on the wrong game version, it says which build to get instead of crashing.

An update to the U60 beta, built from the u60 branch.

New

• Exact worldgen (Moono Tweaks, on by default): a seed now makes the same map as in the original game. Worldgen ran the same steps but rounded floating-point math slightly differently, which shifted biome borders and abyssalite. Reported in #66 by @Tenzian.

Faster

• The engine allocates about another third less memory per frame on a late-game colony, so garbage collections come less often.

Fixes

• Saves with a care package that hadn't opened yet failed to load and crashed shortly after. They now load as in the original. Reported in #69 by @Estenee.
• Updating mods from the main menu with Mod Manager no longer freezes the game until Windows closes it. Reported in #65 by @braziliancara.
• The RivaTuner / MSI Afterburner overlay shows with OpenGL too. With Vulkan it already worked. Reported in #64 by @hao7259.
• Hover cards lay out text that changed this frame at its new width, as in the original. Mods that measure hover text (such as Thermal Tooltips Reworked) line up again. Reported in #70 by @NsPro04.
• On high-DPI screens the mouse pointer is the same size as in the original. It was smaller at 150% and 200% scaling. Reported in #62 by @Crazyboy233.
• When a coroutine throws, Klei's error dialog and the log show the same stack trace as in the original, not Moono's internals.
• The crash window names a hang ("ended by Windows as not responding") instead of only showing its code.

Built by GitHub Actions from commit c6845ca (build) and attested. How to verify a download.

Install or update: download the archive for your system and extract it.

• Windows: double-click oni-moono\player\OniMoono.exe to play, or run setup.cmd once to start Moono from Steam's Play button instead.
• Linux: run ./setup.sh in the oni-moono folder.

If you already set it up, running the new setup is enough.

2026.11.09.01

For the normal game (U59). Playing the U60 public test (Steam beta public_testing)? Use the latest U60 build instead.

New

• On Windows, if Moono crashes, a window now says so and offers Report on GitHub: it opens a pre-filled issue and puts the error, Player.log and the crash dump in one zip, ready to attach. Moono keeps only the two newest crash dumps.
• Steady display during saves and loads (Moono Tweaks, on by default): while the game is busy saving or loading, Moono keeps showing the last frame instead of none, so variable-refresh monitors no longer flicker or go dark during autosaves. Reported in #60 by @isochronous.
• If a game update changes something a Moono tweak relies on, that tweak now turns itself off and shows as Not available in Moono Tweaks, instead of stopping the game from starting.
• Fetch checks by pile (Moono Tweaks, off by default): Duplicants looking for things to fetch check each pile of identical items once, not item by item. On a colony with lots of loose debris, the fetch work on the main thread drops from about 3 ms to 0.4 ms per update.
• OniMoono.exe can now also be started on its own: it finds the game through Steam and starts it, no launch options needed. Steam Cloud then backs up your saves the next time the game starts from Steam.

Faster

• No pause a minute into play: the first large garbage collection now happens at the end of loading, while the game is still paused (about 0.4 s there instead of a stutter later).
• Less memory, faster loads: on a large late-game colony, about 0.6 to 1 GB less memory and loading about a second faster.
• The engine allocates about a third less memory per frame on a late-game colony and half on a mid-game one, so the longer garbage collection pauses come about half as often.
• With Fast Track's Use Mesh Renderers on, culling its mesh renderers is about ten times cheaper.
• UI elements made fully transparent are skipped as in the original, so mods that hide icons that way (such as Pipe Flow Overlay) no longer cost frame time while hidden.
• UI hit tests are reused while nothing under the pointer changes.

Fixes

• Geothermal vents now count everything they emit. At high frame rates they could stop counting, so "kg remaining" stalled and their pipes clogged. This is a bug in the base game that Klei fixed in U60; Moono backports the fix (Geothermal vent fix, on by default). Reported in #61 by @optosi.
• Objects set to the position they already have no longer report a change, as in the original.
• Fast animation events steps aside for mods that patch the same animation events.
• Mods that patch the same shared method now apply in Harmony's own order.

Built by GitHub Actions from commit 02fb381 (build) and attested. How to verify a download.

Install or update: download the archive for your system and extract it.

• Windows: double-click oni-moono\player\OniMoono.exe to play, or run setup.cmd once to start Moono from Steam's Play button instead.
• Linux: run ./setup.sh in the oni-moono folder.

If you already set it up, running the new setup is enough.

2026.11.09.02 (U60 Beta)

Only for Oxygen Not Included's U60 public test (game build 762230, Steam beta public_testing). On the normal game, use the latest normal release. If this build is started on the wrong game version, it says which build to get instead of crashing.

An update to the U60 beta, built from the u60 branch.

New

• Moono now targets U60 build 762230, which fixes the disease-overlay crash itself, so Moono's fix for it is removed.
• On Windows, if Moono crashes, a window now says so and offers Report on GitHub: it opens a pre-filled issue and puts the error, Player.log and the crash dump in one zip, ready to attach. Moono keeps only the two newest crash dumps.
• Steady display during saves and loads (Moono Tweaks, on by default): while the game is busy saving or loading, Moono keeps showing the last frame instead of none, so variable-refresh monitors no longer flicker or go dark during autosaves. Works with Vulkan too. Reported in #60 by @isochronous.
• If a game update changes something a Moono tweak relies on, that tweak now turns itself off and shows as Not available in Moono Tweaks, instead of stopping the game from starting.
• Fetch checks by pile (Moono Tweaks, off by default): Duplicants looking for things to fetch check each pile of identical items once, not item by item. On a colony with lots of loose debris, the fetch work on the main thread drops from about 3 ms to 0.4 ms per update.
• OniMoono.exe can now also be started on its own: it finds the game through Steam and starts it, no launch options needed. Steam Cloud then backs up your saves the next time the game starts from Steam.

Faster

• No pause a minute into play: the first large garbage collection now happens at the end of loading, while the game is still paused.
• The engine allocates about a third less memory per frame on a late-game colony and half on a mid-game one, so the longer garbage collection pauses come about half as often.
• With Fast Track's Use Mesh Renderers on, culling its mesh renderers is about ten times cheaper.
• UI elements made fully transparent are skipped as in the original, so mods that hide icons that way (such as Pipe Flow Overlay) no longer cost frame time while hidden.
• UI hit tests are reused while nothing under the pointer changes.

Fixes

• Objects set to the position they already have no longer report a change, as in the original.
• Fast animation events steps aside for mods that patch the same animation events.
• Mods that patch the same shared method now apply in Harmony's own order.

Built by GitHub Actions from commit de4679e (build) and attested. How to verify a download.

Install or update: download the archive for your system and extract it.

• Windows: double-click oni-moono\player\OniMoono.exe to play, or run setup.cmd once to start Moono from Steam's Play button instead.
• Linux: run ./setup.sh in the oni-moono folder.

If you already set it up, running the new setup is enough.