diff --git a/.forgejo/workflows/ci.yml b/.forgejo/workflows/ci.yml
index 4d5297ea..807f8fb4 100644
--- a/.forgejo/workflows/ci.yml
+++ b/.forgejo/workflows/ci.yml
@@ -315,12 +315,10 @@ jobs:
           echo "build_key=$BUILD_KEY" >> $GITHUB_OUTPUT
           echo "channel=$CHANNEL" >> $GITHUB_OUTPUT
 
-      - name: Free disk space
-        # Prunes unused containers and images, and caps the BuildKit cache at
-        # 5 GB so the package caches survive but old layers don't pile up.
-        run: |
-          docker system prune -af || true
-          docker builder prune --keep-storage 5g -f || true
+      # No disk-space prune step: the runner's Docker daemon is shared, and
+      # `docker system prune -af` here deleted images other repos' jobs had
+      # just pulled and were about to start (CI-runner #16). The runner host
+      # prunes nightly instead.
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v4