The mod Belt Balancer 2 (2.0.9) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event belt-balancer-2::on_player_mined_entity (ID 69)
belt-balancer-2/objects/balancer.lua:140: attempt to index local 'stack_belt' (a nil value)
stack traceback:
belt-balancer-2/objects/balancer.lua:140: in function 'recalculate_nth_tick'
belt-balancer-2/objects/belt.lua:359: in function 'remove_belt'
belt-balancer-2/control.lua:153: in function <belt-balancer-2/control.lua:134>

So i figured out how to remove them. I had to remove certan parts to avoid it crashing. It was apperently a "turbo underground belt" going into the belt balancer that would crash the game when trying to remove it.

I now have the problem again but i tried doing what i did last time but it's not working.

same error here

It just got the error and tried to figure out which balancer, or what belt caused it. It turned out that in my case it was a underground belt which caused the error. The solution was to manually remove it, and then place it again. Upgrading it causes the error.

I just got this same error and tried to figure out which balancer or what belt caused it. It turned out that in my case it was a underground belt which caused the error. The solution was to manually remove it, and then place it again. Upgrading it causes the error.