If you start getting the following error when running hugo server:

WARN 2021/04/10 17:51:51 found no layout file for "HTML" for kind "home": You should create a template file which matches Hugo Layouts Lookup Rules for this combination.

That’s because you probably lost the themes you had installed.

In my case I use Git Modules so to fix it I did the following:

git submodule init
git submodule update

After that I got my themes back and everything was running fine again.

I hope you find it useful, Cheers.