diff --git a/pkgs/kde/plasma/plasma-workspace/default.nix b/pkgs/kde/plasma/plasma-workspace/default.nix
index 24e41b971cf0..42f46eef5eb0 100644
--- a/pkgs/kde/plasma/plasma-workspace/default.nix
+++ b/pkgs/kde/plasma/plasma-workspace/default.nix
@@ -31,6 +31,11 @@ mkKdeDerivation {
     })
   ];
 
+  postInstall = ''
+    # Prevent patching this shell file, it only is used by sourcing it from /bin/sh.
+    chmod -x $out/libexec/plasma-sourceenv.sh
+  '';
+
   extraNativeBuildInputs = [pkg-config spirv-tools];
   extraBuildInputs = [
     qtsvg