diff --git a/artiq-fast/wfvm/autounattend.nix b/artiq-fast/wfvm/autounattend.nix
index 89937de..66744b7 100644
--- a/artiq-fast/wfvm/autounattend.nix
+++ b/artiq-fast/wfvm/autounattend.nix
@@ -8,7 +8,7 @@
 , systemLocale ? "en-US"
 , users ? {}
 , productKey ? null
-, defaultUser ? null
+, defaultUser ? "wfvm"
 , setupCommands ? []
 , timeZone ? "UTC"
 , services ? {}