diff --git a/flake.nix b/flake.nix
index b269d86..fab84bc 100644
--- a/flake.nix
+++ b/flake.nix
@@ -102,8 +102,8 @@
                 ];
                 preStart = if !sync.skipFullSync then (''
                   mkdir -p ${sync.target}
-                  photocatalog -source ${sync.source} -target ${sync.target} -mode ${sync.mode}
-                '' ++ lib.mkIf sync.overwrite "-overwrite") else null;
+                  photocatalog -source ${sync.source} -target ${sync.target} -mode ${sync.mode} ${lib.mkIf sync.overwrite "-overwrite"}
+                '') else null;
                 script = "photocatalog -source ${sync.source} -target ${sync.target} -skip-full-sync -watch -mode ${sync.mode}" ++ lib.mkIf sync.overwrite "-overwrite";
                 serviceConfig = {
                   Type="simple";