Hi,
We had a crash - multiplayer, many mods.
Just as "Uranium scanning finished researching, we got this crash. It is repeatable.

4565.296 Info ServerMultiplayerManager.cpp:977: updateTick(4757753) received stateChanged peerID(1) oldState(ConnectedLoadingMap) newState(TryingToCatchUp)
4568.430 Info ServerMultiplayerManager.cpp:977: updateTick(4757941) received stateChanged peerID(1) oldState(TryingToCatchUp) newState(WaitingForCommandToStartSendingTickClosures)
4568.430 Info InputActionHandler.cpp:5063: UpdateTick (4757941) processed PlayerJoinGame peerID(1) playerIndex(6) mode(connect)
4568.511 Info ServerMultiplayerManager.cpp:977: updateTick(4757946) received stateChanged peerID(1) oldState(WaitingForCommandToStartSendingTickClosures) newState(InGame)
4605.932 Error MainLoop.cpp:1488: Exception at tick 4760191: The mod Ribbon Maze (fix for 2.1) (2.1.78) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event RibbonMaze21::on_research_finished (ID 22)
RibbonMaze21/control/maze-control.lua:808: attempt to index field 'maze' (a nil value)
stack traceback:
RibbonMaze21/control/maze-control.lua:808: in function 'resourceScanning'
RibbonMaze21/control/maze-control.lua:834: in function <RibbonMaze21/control/maze-control.lua:824>
4605.932 Error ServerMultiplayerManager.cpp:85: MultiplayerManager failed: "The mod Ribbon Maze (fix for 2.1) (2.1.78) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event RibbonMaze21::on_research_finished (ID 22)
RibbonMaze21/control/maze-control.lua:808: attempt to index field 'maze' (a nil value)
stack traceback:
RibbonMaze21/control/maze-control.lua:808: in function 'resourceScanning'
RibbonMaze21/control/maze-control.lua:834: in function <RibbonMaze21/control/maze-control.lua:824>"
4605.932 Info ServerMultiplayerManager.cpp:809: updateTick(4760191) changing state from(InGame) to(Failed)
4605.932 Info SteamContext.cpp:458: Leaving lobby...

Hi hyspeed, thanks for reporting this bug, :D

I tested the research, but can´t figure how to replicate the bug, could you give me the mods that are you using?

If it´s a large list, in Windows go to "%AppData\Factorio\mods" (in Linux are in "~/.factorio/mods"), open "mod-list.json" file, copy all and paste here.

Hi Raphal,
I have a save file where it crashes - and one where it doesn't.
Save "_20" will crash, but "_26" will not. I suspect something in the maze got explored, so the scanning function didn't barf.

https://drive.google.com/drive/folders/1_n8uWZseqtUf9lwmpct5KUAzxSwfwzI0?usp=sharing

Let me know if you have issues accessing the files. And yes, we use lots of mods. :)
thanks for the interesting maze mod - we are enjoying it.

Thanks for the save, I fixed it for the next version (2.1.83).

Let me know if you're having more errors, i'll try to fix asap, :D

Happy playing!

We had a great time playing it!
We got arty and it just wrecked them. Good stuff.

It did take a bit of tinkering to figure out the arty that terraforms the maze. We couldn't figure out how to control where it fired. So we watched the turret and if it turned too far, we picked it up and tried again. Cleve feature, that is.

Oh, sorry, the artillery remote is broken from 2.0 and i'm trying to fix it in my free time, but I pushed compatibility with Space Age first.