diff --git a/.github/workflows/pytest-legacy.yml b/.github/workflows/pytest-legacy.yml
index 202d13fe9..ffc8ced92 100644
--- a/.github/workflows/pytest-legacy.yml
+++ b/.github/workflows/pytest-legacy.yml
@@ -66,7 +66,7 @@ jobs:
     #  install root project
     #------------------------
     - name: Install library
-      run: poetry install --no-interaction
+      run: poetry install --no-interaction --only-root
 
     - name: Test with pytest
       run: poetry run pytest tests