diff --git a/docs/README.md b/docs/README.md
index 4315116f8..8b487b8cf 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -5,4 +5,13 @@
 1. Run ./bin/install-dependencies.sh
 2. Run ./bin/generate-docs.sh
 
-It will generate the documentation into the build directory of the checkout.
\ No newline at end of file
+It will generate the documentation into the build directory of the checkout.
+
+
+## Theme issues
+
+If you get a "Theme error", check if the `en/_theme` subdirectory is empty,
+in which case you will need to run:
+
+1. git submodule init
+2. git submodule update