Yesterday I had a really difficult time with pulling in a submodule from an old git repository I had laying around. I thought a quick
Finally I found a answer on StackOverflow1 that put me in the right direction, but that also didn't work. Eventually I gave up and did what I should have done in the first place: Look at the Git documentation for the submodule command2.
The command I ran (from the root of my git folder) that worked for me after I cloned my repository was:
git submodule update --init --recursive
Lesson learned: If there is documentation available, consult that first.