diff --git a/nixos/tests/installer.nix b/nixos/tests/installer.nix
index 84fdb027ed85..cbfdad8d76bb 100644
--- a/nixos/tests/installer.nix
+++ b/nixos/tests/installer.nix
@@ -30,6 +30,8 @@ let
 
         hardware.enableAllFirmware = lib.mkForce false;
 
+        services.udev.allowImpurePaths = false;
+
         ${replaceChars ["\n"] ["\n  "] extraConfig}
       }
     '';
@@ -185,6 +187,8 @@ let
 
             hardware.enableAllFirmware = mkForce false;
 
+            services.udev.allowImpurePaths = false;
+
             # The test cannot access the network, so any packages we
             # need must be included in the VM.
             system.extraDependencies =