Duplicant AI is Horribly Broken

I too am seeing strange behaviour, it resolves upon a reload. In the first pic, they delivered the resources but would not build the tile. 

 

I just had a dupe go in and out of a rocket module for a full cycle - just at the door - in and out, in and out.

Quote

 Reloading the save fixes the issue, but I cant go minutes without the issue happening again.

@Genguin Could you please attach your save file? We are trying to get a reliable way to reproduce the bug.

Same with @nottheonlyonenz and @drizzt515

@EricKlei, the save file only covers the last 10 cycles, there has not been any odd behaviour during this time, it seems to have resolved after the last patch, would you still like it?

 

Yes please. We have fixed some pathfinding issues in the hotfix earlier this week and today but don't have reason to believe they fix the root issue. It's possible that it will happen less often or not at all, we won't know without more data.

If it happens again here's how you can help us troubleshoot it:
1. Select a Duplicant and click "Show Navigation" in the side screen and take a screenshot of the area to attach to this bug report.
2. Select a Duplicant and click the "Move To" button and hover over each tile in the area to see which tiles are not reachable when they should be. Select other Duplicants
3. Select other Duplicants and confirm their ability to move to those tiles is consistent. We're wondering if it's some Duplicants or all of them.
4. Does building a Tile beside an unreachable area and deconstructing it fix the issue?
 

@EricKlei a user on reddit seems to be experiencing the same problem and has posted an intriguing screenshot/description:

Quote

Everyone just sits Idle or does other jjobs within the ~50 tile radius of the Pod.

 

Seems to me like reachability is not getting updated for any duplicant, for some reason.

https://www.reddit.com/r/Oxygennotincluded/comments/1p8q5ne/

The sub has had several other reports of this, and I've noticed that some have had this multiple-ladder-shaft. Though that might just be players trying to remedy the issue after it has appeared:

• https://www.reddit.com/r/Oxygennotincluded/comments/1p6m1rz/somebody_please_explain_why_he_wouldnt_go_down/
• https://www.reddit.com/r/Oxygennotincluded/comments/1p7cimp/is_this_a_bug_why_is_it_unreachable/
• https://www.reddit.com/r/Oxygennotincluded/comments/1p6294d/i_cant_understand_why_my_dupes_cant_reach_these/
• https://www.reddit.com/r/Oxygennotincluded/comments/1p5ww7r/ghost_tiles_blocking_dupes_can_anyone_help/
• https://www.reddit.com/r/Oxygennotincluded/comments/1p5k7m3/bugs_after_patch/
• https://www.reddit.com/r/Oxygennotincluded/comments/1p4ra12/duplicants_spawning_and_getting_stuck_and_dying/
• https://www.reddit.com/r/Oxygennotincluded/comments/1p4pw4a/how_is_this_not_reachable/

I hope it's okay to direct any more users I see there to this bug report.

Having the same issue and also not understanding what the point even would be to submit a save file?  Because the problem is resolved with a save-and-reload, the problem is obviously not stored in save files.  It's an active code base issue and reproducing it requires actively playing the game.

Edited November 28, 2025 by Jaggid Edje

9 minutes ago, Jaggid Edje said:

understanding what the point even would be to submit a save file?

The save file is a necessary condition. A week ago I started a new save on the skewed lab map and never hit the issue, so clearly it's difficult to replicate. Help the devs out by eliminating unknown factors, maybe?

So many me-too's here, on reddit, and discord, and not a single save file was provided. ¯\_(ツ)_/¯

@myxal, I guess that makes sense.   I had been experiencing this a few times every play session other than the very early game in my last playthrough.   I started a new playthrough yesterday and haven't seen it happen since.

I did also remove the command line argument -UseAllAvailableCores before starting this playthrough, so I thought maybe that was a factor.  But based on your comment it could just be because it's a different playthrough.

Save files can be useful even though this bug does not survive reloading the game. It provides further context to a report such as the seed so we can recreate the world and inspect the area, examine any door permissions, see where suit checkpoints are etc. 

@myxal Thanks for compiling the reddit posts and sending players our way. We have been monitoring these posts too.

If you or anyone else doesn't mind playing with dev debug mode there's additional information you can provide us. Note that in doing so it disables achievements for that save and may affect your save file in other ways so it's recommended you back it up first. Advanced users only.

Spoiler

1. Enable dev debug by typing "kleiplay" on the title screen. The last letter in the build watermark should be "D".

2. Press Ctrl + ` (backtick) to open dev debug tools. Accept the warning.

3. Open the "Sim Debug" debugger.

4. Select the "MinionGroupProber" debug mode. Tiles which are reachable by one or more Duplicants are drawn as white.

6. Take a screenshot of the problematic areas. It's possible the area is still white since other Duplicants can reach it. Take a screenshot of "Show Navigation" too.

7. Use Sandbox destroy tool to remove all but one of the stuck Duplicants.

8. Take a screenshot of the area they should be able to reach. If the bug is what we think it is, this area should not be highlighted white. As to how the game gets into this state we are still investigating. Take a screenshot of "Show Navigation" too.

9. Use instant build mode to construct a Tile nearby. The area in a small radius around it should be updated. Take a screenshot of this and also the "Show Navigation" of the Duplicant.

Thanks for all the information and your patience as we continue to investigate this bug.

@EricKlei thanks for the instructions - I don't suppose the dev debug is functional in the native Linux build? I'm just getting a crash after hitting Ctrl + `

Spoiler

EntryPointNotFoundException: SetKAssertCB assembly:<unknown assembly> type:<unknown type> member:(null)
  at (wrapper managed-to-native) KImGuiUtil.SetKAssertCB(KImGuiUtil/KAssertCB)
  at ImGuiRenderer.Init () [0x00014] in <ab7eff41dff142799ffe3a55f2eb5a35>:0 
  at ImGuiRenderer.NewFrame () [0x00007] in <ab7eff41dff142799ffe3a55f2eb5a35>:0 
  at Global.Update () [0x0004b] in <d00d6f304bec4bff9ba8d620abb19b92>:0 
UnityEngine.DebugLogHandler:Internal_LogException(Exception, Object)
UnityEngine.DebugLogHandler:LogException(Exception, Object)
LogCatcher:UnityEngine.ILogHandler.LogException(Exception, Object)
UnityEngine.Logger:LogException(Exception, Object)
UnityEngine.Debug:CallOverridenDebugHandler(Exception, Object)

[23:04:03.597] [1] [INFO] Checking which steam branch we're on. Got: []
Caught fatal signal - signo:11 code:1 errno:0 addr:0x1c90

Obtained 21 stack frames.
#0  0x007f2bd98262c0 in __sigaction
#1  0x007f2b3e060f28 in ImGui::Render()
#2  0x00000042faa327 in (wrapper managed-to-native) ImGuiNET.ImGuiNative:igRender ()
#3  0x00000042faa29b in ImGuiNET.ImGui:Render ()
#4  0x00000042faa243 in ImGuiRenderer:EndFrame ()
#5  0x0000004283a913 in Global:LateUpdate ()
#6  0x00000041dbbf85 in (wrapper runtime-invoke) object:runtime_invoke_void__this__ (object,intptr,intptr,intptr)
#7  0x007f2b3ec46428 in mono_get_runtime_build_info
#8  0x007f2b3ede578f in mono_runtime_invoke
#9  0x007f2b3ede56d9 in mono_runtime_invoke
#10 0x007f2bda7f6af2 in (Unknown)
#11 0x007f2bda7e3e52 in (Unknown)
#12 0x007f2bda7d58a1 in (Unknown)
#13 0x007f2bda45d926 in (Unknown)
#14 0x007f2bda5eda87 in (Unknown)
#15 0x007f2bda5eda41 in (Unknown)
#16 0x007f2bda5edd67 in (Unknown)
#17 0x007f2bda86627b in PlayerMain(int, char**)
#18 0x007f2bd980f5b5 in __libc_start_call_main
#19 0x007f2bd980f668 in __libc_start_main
#20 0x00000000201029 in (Unknown)

No issue under Proton, though.

Ah sorry, it doesn't work on Linux.

On 11/28/2025 at 2:17 PM, EricKlei said:

If you or anyone else doesn't mind playing with dev debug mode there's additional information you can provide us. Note that in doing so it disables achievements for that save and may affect your save file in other ways so it's recommended you back it up first. Advanced users only.

Instead of playing with debug mode on, would it be just as useful for you if I play with the Debug Buttons mod enabled so that I can switch Debug mode on from within a playthrough if/when the problem comes up?  The mod would basically allow me to switch on Debug mode only when it is needed, but the debug functionality is the same.  Or is there some additional information logged into a save file when debug is enabled that would make that less useful?

 

I did not notice anything in these cycles, there was issues at cycles 112, 193 and 252. I am not sure this will be of any use to you, sorry.

The Plucky Committee Cycle 312.sav The Plucky Committee Cycle 313.sav The Plucky Committee Cycle 314.sav The Plucky Committee Cycle 315.sav The Plucky Committee Cycle 316.sav The Plucky Committee Cycle 317.sav The Plucky Committee Cycle 318.sav The Plucky Committee Cycle 319.sav The Plucky Committee Cycle 320.sav The Plucky Committee Cycle 321.sav The Plucky Committee.sav

On 11/30/2025 at 2:44 AM, Jaggid Edje said:

Instead of playing with debug mode on, would it be just as useful for you if I play with the Debug Buttons mod enabled so that I can switch Debug mode on from within a playthrough if/when the problem comes up?  The mod would basically allow me to switch on Debug mode only when it is needed, but the debug functionality is the same.  Or is there some additional information logged into a save file when debug is enabled that would make that less useful?

Using that mod to selectively enable debug mode should be fine.

18 hours ago, nottheonlyonenz said:

I did not notice anything in these cycles, there was issues at cycles 112, 193 and 252. I am not sure this will be of any use to you, sorry.

Thanks for the information. Do you recall you played the game continuously between those cycles? e.g. restarted at cycle 12, played until 193, restarted, played until 252? Could you point me to which areas you saw them getting stuck?

I did dump the clips, perhaps they will be helpful. I did play continuously between the restarts.

https://www.youtube.com/watch?v=gr0FGp1mPM0

https://www.youtube.com/watch?v=VZ1S2JA5Rw4

https://www.youtube.com/watch?v=48YZn6lVkeQ

 

Edit, it only seems to have been Harold having troubles, he was also the builder (re: the tile not being built pic)

Another edit, Harold was the only builder/digger, so both of his priorities for those tasks were the highest.

In the bottom pic, has something changed with priorities? Harold should be focused on building and digging but storing was his next errand, it seems they really go off the priority number not the arrows in the jobs section now. (I have been playing since Oct 2017) and it really seems something has changed. Apologies for the multiple edits.

 

Harold would not move to this location, but when I restarted he did.

 

The dupes delivered materials to this tile, but no one would build it, so another restart and it came right   .

Edited December 2, 2025 by nottheonlyonenz

Appreciate the videos and details, thanks!

Here's another dev debug step which could be useful in debugging the issue. This would be useful to confirm something we suspect is happening.

Spoiler

Enable debug mode (see my previous post for instructions)

1. Open Debuggers -> Nav Grid.
2. Zoom in as close as you can. The game will crash if you are zoomed too far out.
3. Click "Draw Links" and take a screenshot.

 

Hopefully this is helpful.

@Vertel Thanks for the screenshot. Did you notice Duplicants not being able to path through the area? Are all those relocates to the same destination on the right? Did reloading the save fix the issue?

I started a new playthrough a few days ago.  On my previous playthrough I was having these issues semi-frequently.   Every 5-10 or so cycles I would need to save and reload.  On the new one I did not experience any issues until cycle 59, and after the save and reload to 'fix' it I began experiencing the problem every 5-10 cycles or so in that playthrough as well.   

It then occurred to me that my issues didn't start until after I built a staircase (from the Stairs mod) for the first time in that playthrough so I disabled the mod and rolled back to a save before I had ever built anything from the mod (and before I had any issues like in this thread).  Since that roll back, I have again had 0 issues and have played another 35 or so cycles.

I am not saying the Stairs mod was responsible and that it isn't a core-game bug, but at the very least doing a roll back to a point before I had any issues at all seemed to help, as it returned the playthrough to a problem-free state longer term.   This suggests that, at the very least, there may be something related to the bug stored in the save file after all unless the Stairs mod was indeed confounding the issue. (or not; obviously it could just be a coincidence).  

I also am leaving the Stairs mod disabled to see if the problem ever crops up again (for me) without that mod active.   So far, it has not.  I am now ready to provide debug screenshots with the information requested above if it should happen again though, so I'll have more useful data then.

Edited December 2, 2025 by Jaggid Edje

On 12/3/2025 at 3:48 AM, EricKlei said:

@Vertel Thanks for the screenshot. Did you notice Duplicants not being able to path through the area? Are all those relocates to the same destination on the right? Did reloading the save fix the issue?

Duplicants were able to path through that area but not able to pick up those specific items. The destination was a location further up the ladder on the left, no issues with pathing to that general location. Reloading did solve it.

Changed Status to Closed

@Jaggid Edje That helps a lot, the stairs mod has a bug which results in pathfinding updates being disabled and happens quite frequently. When this occurs the affected Duplicant can still navigate to some areas using cached data, just not new areas. It looks like the mod author is aware of the issue as they wrote "Working in Progress: Rework pathfinding method to fix some issue" on their workshop page.

@Genguin the stairs mod bug was the source of your initial bug report. I've marked this as closed but we are still investigating other reports of pathfinding.

Awesome that you guys sorted it out.  I was going to circle back here today just to confirm that I was confident the issue (in my game at least) was definitely a problem with the Stairs mod because with it disabled I had now played ~200 cycles without issues at all.   

Edited December 4, 2025 by Jaggid Edje