diff --git a/pkgs/games/prismlauncher/default.nix b/pkgs/games/prismlauncher/default.nix
index 2761ab22f907..2e7defef059d 100644
--- a/pkgs/games/prismlauncher/default.nix
+++ b/pkgs/games/prismlauncher/default.nix
@@ -11,7 +11,7 @@
 , tomlplusplus
 , ghc_filesystem
 , gamemode
-, msaClientID ? ""
+, msaClientID ? null
 , gamemodeSupport ? true
 }:
 let
@@ -42,7 +42,7 @@ stdenv.mkDerivation rec {
     tomlplusplus
   ] ++ lib.optional gamemodeSupport gamemode;
 
-  cmakeFlags = lib.optionals (msaClientID != "") [ "-DLauncher_MSA_CLIENT_ID=${msaClientID}" ]
+  cmakeFlags = lib.optionals (msaClientID != null) [ "-DLauncher_MSA_CLIENT_ID=${msaClientID}" ]
     ++ lib.optionals (lib.versionAtLeast qtbase.version "6") [ "-DLauncher_QT_VERSION_MAJOR=6" ];
 
   postUnpack = ''