diff --git a/product.py b/product.py
index 1fb1e0a5..3c6a3682 100644
--- a/product.py
+++ b/product.py
@@ -548,6 +548,10 @@ def findXenSourceBackups():
                 logger.log("findXenSourceBackups: ignoring later platform: %s > %s" %
                            (backup.version, THIS_PLATFORM_VERSION))
                 raise StopIteration()
+            if not os.path.exists(backup.root_disk):
+                logger.error("findXenSourceBackups: PRIMARY_DISK=%r does not exist" %
+                             (backup.root_disk,))
+                raise StopIteration()
 
             backups.append(backup)