diff --git a/modules/c3d2.nix b/modules/c3d2.nix
index 230f234d..f15493d9 100644
--- a/modules/c3d2.nix
+++ b/modules/c3d2.nix
@@ -383,7 +383,6 @@ in
 
       nix = {
         settings = {
-          auto-optimise-store = true;
           trusted-public-keys = lib.mkIf (config.networking.hostName != "hydra") [
             (builtins.readFile ../hosts/hydra/cache-pub.key)
           ];