diff --git a/artiq-fast/wfvm/win.nix b/artiq-fast/wfvm/win.nix
index b7776bd..789e3b0 100644
--- a/artiq-fast/wfvm/win.nix
+++ b/artiq-fast/wfvm/win.nix
@@ -1,5 +1,5 @@
 { pkgs
-, diskImageSize ? "22G"
+, diskImageSize ? "70G"
 , windowsImage ? null
 , autoUnattendParams ? {}
 , impureMode ? false