diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 802c445..9e96650 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -28,6 +28,7 @@ jobs:
           environment-file: environment.yml
           miniforge-version: latest
           use-mamba: true
+          conda-remove-defaults: "true"
       - name: Install development packages
         run: pip install --requirement requirements.txt
       - name: Check formatting