diff --git a/mybinder/templates/buildkit-pruner.yaml b/mybinder/templates/buildkit-pruner.yaml
index 6030a43f4..fa4148ba7 100644
--- a/mybinder/templates/buildkit-pruner.yaml
+++ b/mybinder/templates/buildkit-pruner.yaml
@@ -26,7 +26,7 @@ spec:
             - /bin/sh
             - -c
             - |
-              docker image prune ---force --all && \
+              docker image prune --force --all && \
               docker builder prune --force --all --keep-storage={{ .Values.buildkitPruner.buildkitCacheSize }} && \
               docker system df
             volumeMounts: