Мод Belt Balancer (Improved Performance) (3.1.1) вызвал неустранимую ошибку.
Пожалуйста, сообщите об этой ошибке автору мода.

Error while running event belt-balancer-performance::on_nth_tick(1)
invalid key to 'next'
stack traceback:
[C]: in function 'next'
belt-balancer-performance/objects/balancer.lua:213: in function 'run'
belt-balancer-performance/helper/message-handler.lua:33: in function <belt-balancer-performance/helper/message-handler.lua:31>

Please try updating the mod, I recently released a fix for this in 3.1.2
I think this is caused by an edge case while replacing a belt in the output of a balancer, and might be more likely with only one output belt, express belts, and robots.
So if you remember/know, could you tell me the following information:
How many output belts were on the balancer?
What was the highest tier of belt?
Were you using robots to replace (upgrade) belts at the time?

sorry i didn't response
im using autoupgrade mod which is updates belts (and other stuff) automaticaly with robots. So my crash was not when i am replace belts by hand and it wasnt on my sight. But i think that it could be automatic upgrade by robots. Probably it was uprgade from tier 2 to 3 (red to blue)

I cant test your new version, cause i dont have that savegame any more, sorry i should think about it before and put that savegame file to a save place, but i did not

Still getting this issue when bots autoupgrade belts next to balancers

Still getting this issue when bots autoupgrade belts next to balancers

I can't reproduce the error, so make sure you are on the latest version, and if you get the error again can you please include the error or a screenshot of it.

https://imgur.com/a/WHCH76O
I got this error, and now, whenever i load an autosave, i get the error immediately, making the game unplayable

The error should be fixed in version 3.1.3, so can you please try updating your mods (you can do this in the mods menu). The error isn't very useful when the code it's referencing no longer exists.