diff --git a/lib/spack/spack/test/mirror.py b/lib/spack/spack/test/mirror.py
index 046ec56604..f83cc8090c 100644
--- a/lib/spack/spack/test/mirror.py
+++ b/lib/spack/spack/test/mirror.py
@@ -102,6 +102,7 @@ def check_mirror(self):
                 spec = Spec(name).concretized()
                 pkg = spec.package
 
+                pkg._stage = None
                 saved_checksum_setting = spack.do_checksum
                 try:
                     # Stage the archive from the mirror and cd to it.