I get this message at game startup with the latest update:

2.492 Error ModManager.cpp:1758: Unknown collision mask "out_of_map"

Source: tomwub-pipe (pipe).

What mods do you have enabled?

I'm not them, but I had the same experience this morning. I have up to date Factorio (portable install) and a ton of mods. After disabling all mods except Space Age stuff, it still did it. Finally, I disabled everything except the base game and AUP and it still gives this exact same error.

1.20 seems to be a no-go
same error and still messing with flow config

The "out_of_map" mask is only present in v2.0.44+. Current Stable is 2.0.43
You have to go enable latest experimental in beta selection on Steam(or wherever else).

well i suppose that's that
everybody thank the monkey

oh strange. that makes sense, then. not sure if i should push a new release... might 'undo' that fix, then refix it with a base version requirement

Fixed in latest release, just hit update and it'll download the correct version for your game version

I'm getting this error after updating to v0.1.21 on Factorio v2.0.43:

Failed to load mods: Unknown collision mask "out_of_map"

Source: tomwub-duct-curve (storage-tank).

Ugh. I never considered the edge case of compat. Hold on

Fixed again

Updated to v0.1.23 on Factorio v2.0.43, which is what the mod indicated it requires of me, and I'm still getting the following:

Failed to load mods: Unknown collision mask "out_of_map"

Source: tomwub-pipe (pipe).

Edit: I think you may have the base version requirement the wrong way around, because changing it to >= 2.0.44 and running the game under Experimental works just fine.

Double Edit: v0.1.24 also works just fine.

v0.1.23 should work fine for base v2.0.43