diff --git a/nixos/lib/make-options-doc/default.nix b/nixos/lib/make-options-doc/default.nix
index 493006c92e7f..44bc25be9238 100644
--- a/nixos/lib/make-options-doc/default.nix
+++ b/nixos/lib/make-options-doc/default.nix
@@ -118,8 +118,9 @@ in rec {
   # The actual generation of the xml file is done in nix purely for the convenience
   # of not having to generate the xml some other way
   optionsXML = pkgs.runCommand "options.xml" {} ''
+    export NIX_STORE_DIR=$TMPDIR/store
+    export NIX_STATE_DIR=$TMPDIR/state
     ${pkgs.nix}/bin/nix-instantiate \
-      --store dummy:// \
       --eval --xml --strict ${./optionsJSONtoXML.nix} \
       --argstr file ${optionsJSON}/share/doc/nixos/options.json \
       > "$out"