diff --git a/Library/Homebrew/cmd/update.sh b/Library/Homebrew/cmd/update.sh
index 716c01599b..acf4520ba6 100644
--- a/Library/Homebrew/cmd/update.sh
+++ b/Library/Homebrew/cmd/update.sh
@@ -425,6 +425,12 @@ EOS
     declare UPSTREAM_BRANCH"$TAP_VAR"="$UPSTREAM_BRANCH_DIR"
     declare PREFETCH_REVISION"$TAP_VAR"="$(git rev-parse -q --verify refs/remotes/origin/"$UPSTREAM_BRANCH_DIR")"
 
+    # Force a full update if we don't have any tags.
+    if [[ "$DIR" = "$HOMEBREW_REPOSITORY" && -z "$(git tag --list)" ]]
+    then
+      HOMEBREW_UPDATE_FORCE=1
+    fi
+
     if [[ -z "$HOMEBREW_UPDATE_FORCE" ]]
     then
       [[ -n "$SKIP_FETCH_BREW_REPOSITORY" && "$DIR" = "$HOMEBREW_REPOSITORY" ]] && continue