diff --git a/pkgs/development/python-modules/paddlepaddle/default.nix b/pkgs/development/python-modules/paddlepaddle/default.nix
index c0a6212a3380..96bdf6a76480 100644
--- a/pkgs/development/python-modules/paddlepaddle/default.nix
+++ b/pkgs/development/python-modules/paddlepaddle/default.nix
@@ -40,7 +40,8 @@ let
         lib.replaceStrings [ "." ] [ "" ] cudaPackages.cudatoolkit.version
       }"."${pyShortVersion}"
     else
-      sources."${stdenv.hostPlatform.system}"."cpu"."${pyShortVersion}";
+      sources."${stdenv.hostPlatform.system}"."cpu"."${pyShortVersion}"
+        or (throw "Unsupported system: ${stdenv.hostPlatform.system}");
   platform = sources."${stdenv.hostPlatform.system}".platform;
   src =
     if cudaSupport then