diff --git a/.github/workflows/run-unit-tests.yml b/.github/workflows/run-unit-tests.yml
index 95ad34f..9b4e995 100644
--- a/.github/workflows/run-unit-tests.yml
+++ b/.github/workflows/run-unit-tests.yml
@@ -143,6 +143,7 @@ jobs:
           package_root: ${{ inputs.package_root }}
       # actions/cache will detect zstd and will become much faster.
       - name: Install zstd
+      if: ${{ steps.swift-check.outputs.swift-compatible == 'true' && (matrix.swift-config.build-mode == 'debug' || inputs.with_release_mode_testing) }}
         run: |
           apt-get update -y
           apt-get install -y zstd