When the rich resources option is on, Factorio spits out an error while loading:
"Failed to load mods: wormmus-config/data.lua:7:
wormmus-config/util/loaders/default.lua:3:
wormmus-config/prototypes/extension/map-generation/resource-spawning-parameters.lua:5:
attempt to index field 'autoplace' (a nil value)."
Using Factorio 0.15.13

What other mods are you using?

All of Bob's, all of Angel's, all of AAI, Creative mode, Omnimatter+wood, RSO, plus a lot of other ones but those are all that I can imagine have anything to do with map generation.

It's probably to do with RSO, beings it changes the entire generation scheme. I will have a fix sometime in the near future. Thank you for your report.

1.4.5 has the possible fix, and is released now.

1.4.5 works for me now, but I tested a separate install of Factorio and 1.4.4 worked fine if RSO was the only other mod, so RSO alone didn't cause the issue.

Then probably something to do with bob's and angel's. I'll work on a fix.

Now it's producing the same error when trying to run without RSO.
EDIT: Bob's plates + ores + rich resources = error
Bob's plates + ores + RSO + rich resources = no error

It has to do with Bob's Mods. I have disabled it if Bob's Mods is installed, even if it's selected to be Enabled. The fix will be in the next patch.

I just released 1.4.6, which has the fix.