diff --git a/lib/System/Unix/Program.inc b/lib/System/Unix/Program.inc
index 1ffd71af10d..56dea250a77 100644
--- a/lib/System/Unix/Program.inc
+++ b/lib/System/Unix/Program.inc
@@ -298,7 +298,13 @@ Program::Kill(std::string* ErrMsg) {
 
   uint64_t pid64 = reinterpret_cast<uint64_t>(Data_);
   pid_t pid = static_cast<pid_t>(pid64);
-  return (kill(pid, SIGKILL) == 0);
+
+  if (kill(pid, SIGKILL) != 0) {
+    MakeErrMsg(ErrMsg, "The process couldn't be killed!");
+    return true;
+  }
+
+  return false;
 }
 
 bool Program::ChangeStdinToBinary(){
diff --git a/lib/System/Win32/Program.inc b/lib/System/Win32/Program.inc
index 87f9e64e4c5..af6cce6de1a 100644
--- a/lib/System/Win32/Program.inc
+++ b/lib/System/Win32/Program.inc
@@ -347,7 +347,12 @@ Program::Kill(std::string* ErrMsg) {
   }
 
   HANDLE hProcess = reinterpret_cast<HANDLE>(Data_);
-  return TerminateProcess(hProcess, 1);
+  if (TerminateProcess(hProcess, 1) == 0) {
+    MakeErrMsg(ErrMsg, "The process couldn't be killed!");
+    return true;
+  }
+
+  return false;
 }
 
 bool Program::ChangeStdinToBinary(){