diff --git a/artiq-fast/windows/run-test.nix b/artiq-fast/windows/run-test.nix
index 24b2cc1..bdbfb1c 100644
--- a/artiq-fast/windows/run-test.nix
+++ b/artiq-fast/windows/run-test.nix
@@ -53,9 +53,11 @@ stdenv.mkDerivation {
     echo "Wait for Windows to boot"
     sleep 10
     ${ssh "ver"}
+    i=0
     for pkg in ${sipycoPkg}/noarch/sipyco*.tar.bz2 ${artiqPkg}/noarch/artiq*.tar.bz2 ; do
-      ${scp "\\$pkg" "to_install.tar.bz2"}
-      ${ssh "anaconda\\scripts\\activate ${condaEnv} && conda install to_install.tar.bz2"}
+      ${scp "\\$pkg" "to_install\\$i.tar.bz2"}
+      ${ssh "anaconda\\scripts\\activate ${condaEnv} && conda install to_install\\$i.tar.bz2"}
+      ((i=i+1))
     done
 
     # Schedule a timed shutdown against hanging test runs