Hi,
Thanks for the great mod, it has come in handy.
While playing I have received the a similar crash on 3 different occasions. The last crash I toggled all other mods to off and tested; the crash is repeating about 30 seconds after my last auto-save. Only one type item being replaced. It also seems to be when I expand the logistic/construction network to a certain area.

Error MainLoop.cpp:788: Exception at tick 2415362: Error while running event on_tick (ID 0)
auto-upgrade/control.lua:125: attempt to index field 'logistic_network' (a nil value)

I have a screen shot, game saves and log files if needed.

Thanks in advance.

Thanks for your report. The error is strange, but I should be able to fix it. It seems like it finds a valid roboport that doesn't have a logistic network. I'm not really sure when that can happen.
In any case, I'll add an extra check to prevent the error, although this may lead to certain entities not being upgraded (basically when the mod can't find another roboport with a valid logistic network and within range of the entity).

There, I fixed it while typing this reply. Unfortunately I can't reproduce the error without the save file, but I think it should be fixed. So please test it for me and if there's still an issue I'd like a copy of your save game so I can debug further.

Let me know how you want it delivered. In the mean time I'll test it on the save that crashed.

OK, so I tested with the save that was crashing and I got no errors. I took a look around and noticed one of my roboports was not connected to power. Maybe the culprit? At any rate, thanks for the quick fix. I'll try using it in my current save and see how it goes.

That's actually quite likely. Didn't occur to me that a roboport without power would not have a logistic network.