I have a map with a bunch of loaders in it that crashes on update with every version after 1.7.9. It crashes with this error:

17.151 Error AppManagerStates.cpp:1402: The mod Miniloader caused a non-recoverable error.
Please report this error to the mod author.

Error while running event miniloader::on_configuration_changed
miniloader/configchange.lua:197: attempt to index field '?' (a nil value)
stack traceback:
miniloader/configchange.lua:197: in function 'f'
miniloader/configchange.lua:162: in function 'forall_miniloaders'
miniloader/configchange.lua:180: in function 'fix_inserter_counts'
miniloader/control.lua:76: in function <miniloader/control.lua:70>

It seems likely that your map is somehow corrupt. You apparently have a miniloader somewhere that has no inserters, which should be impossible. Could you post a link to the save?

I can. And yes, it probably is in some way. I had some weird problems crop up with Picker Dollies before that issue was fixed. I'll get to posting the save soon.

Here is a link to the save. It's 40MiB, so it's a bit largish: https://drive.google.com/file/d/1vbHaGQTuP1o6djYP1SrYD-yyi9tfnGYE/view?usp=sharing

Yep, there were 3 broken miniloaders tucked in the loading station of your iron smelter. Version 1.7.12 includes a migration to clean that up, which allows the map to load.

Thanks. :-)