I am tired of trying to get a challenge then being told the challenge requires extra content.
ACtually today, I have not yet found a single challenge which does NOT require additional content…
Which expansions do you have? One of the the not so great things about the challenges is that when posting or responding it gives you a choice of which dlc is included (and mods) which are automatically checked. I generally try and keep them unchecked but it slips my mind sometimes.
Some mods also include extra’s for the vanilla units - and if they get used the other side needs that mod (Dreadnought mod s is one).
And some people just like adding a few extra things and forget the rest of us can’t use it,
Try and when posting a challenge state what expansions you don’t want.
Berny
Groundhog day?
actually I cant post my own challenge as the software crashes on trying to create a custom challenge - reported as a problem.
Also - I have only the DN expansion - but I do not know if the software recognizes this, as to get the expansion to work I can not do an “install” as it appears that most (All?) of DLC is in PC format - .exe does not play well wih a Mac. 
I got the DNs to work, at least for personal play, by converting the .dds files to .pngs and placing the files in the right place - manually.
For anyone else who might be reading this - you have to ‘view package contents’ of the game to do this.
I did DL other free content - but again, the installer is an .exe. I looked at converting the files to PNG but too many to be bothered.
Strange - I thought i had already converted the .dds files to .png in the Mac Version of the Dreadnought mod . .
Anyways.
Maybe in GSB 2 the Pkg file has a list of all the files it uses - that way if the game detects items from the pkg files it would automatically select what expansion you need to play the challenge.