diff --git a/Building-binary.md b/Building-binary.md
index f6e0dfd..0364c68 100644
--- a/Building-binary.md
+++ b/Building-binary.md
@@ -77,6 +77,9 @@ make docker-extract
 make full
 ```
 
+> [!IMPORTANT]
+The script requires you to enter [a tag](https://github.com/vaultwarden/vw_web_builds/tags) or [a branch of a web-vault](https://github.com/vaultwarden/vw_web_builds/branches) to build. The `main` branch is an out-of-date mirror of the [bitwarden/clients repository](https://github.com/bitwarden/clients/) that has not been patched, so it won't be compatible with Vaultwarden.
+
 #### Old (very manual way):
 
 - Clone the git repository at [bitwarden/clients](https://github.com/bitwarden/clients) and checkout the latest release tag (e.g. v2022.6.0):