diff --git a/pkgs/tools/networking/ookla-speedtest/default.nix b/pkgs/tools/networking/ookla-speedtest/default.nix
index 6f377a0a4bf7..3834355528e9 100644
--- a/pkgs/tools/networking/ookla-speedtest/default.nix
+++ b/pkgs/tools/networking/ookla-speedtest/default.nix
@@ -19,7 +19,7 @@ in
 stdenv.mkDerivation rec {
   inherit pname version;
 
-  src = srcs.${stdenv.hostPlatform.system};
+  src = srcs.${stdenv.hostPlatform.system} or (throw "Unsupported system: ${stdenv.hostPlatform.system}");
 
   setSourceRoot = ''
     sourceRoot=$PWD