Failed to load mods: Error while running setup for space-location prototype "OMNI" (planet): medium-rock (decorative) does not have an autoplace specification.

Mods to be disabled:

Omni, minimalist-rails, diurnal-dynamics, planetslib, cupric-asteroid

Some people have already pointed that out. Apparently, there's some compatibility issue with the mod "alien biomes" and some others. I looked into it, and it didn't seem like something I could solve on my own end. Sorry.

I also ran into this issue. Very frustrating. The loading only fails with Alien Biomes present, although the error message mentions a lot of other mods.

You shouldn't worry about the Alien Biomes incompatibility; many other planet/space age mods are incompatible with Alien Biomes at this point, I think it's better for players to just avoid using it (at least for Space Age)

You shouldn't worry about the Alien Biomes incompatibility; many other planet/space age mods are incompatible with Alien Biomes at this point, I think it's better for players to just avoid using it (at least for Space Age)

proceeding to ignore even more reports