diff --git a/lib/spack/spack/stage.py b/lib/spack/spack/stage.py
index e46354d9633d996a75355a355b0a2cf762154337..ffad242f279a5b9ca806688e733a43990528543b 100644
--- a/lib/spack/spack/stage.py
+++ b/lib/spack/spack/stage.py
@@ -500,6 +500,7 @@ def cache_mirror(self, stats):
             stats.already_existed(absolute_storage_path)
         else:
             self.fetch()
+            self.check()
             spack.caches.mirror_cache.store(
                 self.fetcher, self.mirror_paths.storage_path)
             stats.added(absolute_storage_path)