diff --git a/flake.nix b/flake.nix
index b0f2d2331..7d796bbf5 100644
--- a/flake.nix
+++ b/flake.nix
@@ -506,6 +506,6 @@
   nixConfig = {
     extra-trusted-public-keys = "nixbld.m-labs.hk-1:5aSRVA5b320xbNvu30tqxVPXpld73bhtOeH6uAjRyHc=";
     extra-substituters = "https://nixbld.m-labs.hk";
-    sandboxPaths = ["/opt"];
+    extra-sandbox-paths = "/opt";
   };
 }