diff --git a/artiq/windows/qemu.nix b/artiq/windows/qemu.nix
index 630ce62..c99ad80 100644
--- a/artiq/windows/qemu.nix
+++ b/artiq/windows/qemu.nix
@@ -32,7 +32,7 @@ let
     in "${qemu_kvm}/bin/qemu-system-x86_64 ${argStr}";
 
   # Pass empty config file to prevent ssh from failing to create ~/.ssh
-  sshOpts = "-F /dev/null -o StrictHostKeyChecking=accept-new -o UserKnownHostsFile=/dev/null";
+  sshOpts = "-F /dev/null -o StrictHostKeyChecking=accept-new -o UserKnownHostsFile=\$TMP/known_hosts";
   ssh = cmd: ''
     echo ssh windows '${cmd}'
     ${sshpass}/bin/sshpass -p${sshPassword} -- \
diff --git a/artiq/windows/run-test.nix b/artiq/windows/run-test.nix
index 4988d16..d9a7935 100644
--- a/artiq/windows/run-test.nix
+++ b/artiq/windows/run-test.nix
@@ -51,7 +51,6 @@ stdenv.mkDerivation {
 
     echo "Wait for Windows to boot"
     sleep 10
-    export HOME=`mktemp -d`
     ${ssh "ver"}
     for pkg in ${artiqPkg}/noarch/artiq*.tar.bz2 ; do
       ${scp "\\$pkg" "artiq.tar.bz2"}