diff --git a/fill-disk.sh b/fill-disk.sh
index 7664549e580..3fba3c0619d 100755
--- a/fill-disk.sh
+++ b/fill-disk.sh
@@ -418,6 +418,7 @@ sleep 10;
 
 echo umounting filesystem
 
+umount $root/cdrom
 umount $root
 #umount /nix
 umount /cdrom