diff --git a/.github/workflows/testing.yml b/.github/workflows/testing.yml
index 1ee9406..420d405 100644
--- a/.github/workflows/testing.yml
+++ b/.github/workflows/testing.yml
@@ -23,6 +23,7 @@ jobs:
         channel-priority: strict
         environment-file: .ci_support/environment.yml
         python-version: ${{ matrix.python-version }}
+        use-only-tar-bz2: true # IMPORTANT: This needs to be set for caching to work properly!
 
 
     - name: run tests