diff --git a/pkgs/by-name/rs/rssguard/package.nix b/pkgs/by-name/rs/rssguard/package.nix
index 481135aeb245..05d08dd9b9a8 100644
--- a/pkgs/by-name/rs/rssguard/package.nix
+++ b/pkgs/by-name/rs/rssguard/package.nix
@@ -33,6 +33,10 @@ stdenv.mkDerivation (finalAttrs: {
     qt6.wrapQtAppsHook
   ];
 
+  # This string must have quotes around Release or the package will break!
+  # See https://github.com/NixOS/nixpkgs/issues/563621
+  cmakeBuildType = "\"Release\"";
+
   dontWrapGApps = true;
 
   preFixup = ''