diff --git a/lib/System/Unix/Program.inc b/lib/System/Unix/Program.inc
index 6ff69ca133e..2426900578b 100644
--- a/lib/System/Unix/Program.inc
+++ b/lib/System/Unix/Program.inc
@@ -170,14 +170,21 @@ Program::ExecuteAndWait(const Path& path,
     case 0: {
       // Redirect file descriptors...
       if (redirects) {
+        // Redirect stdin
         if (RedirectIO(redirects[0], 0, ErrMsg)) { return -1; }
+        // Redirect stdout
         if (RedirectIO(redirects[1], 1, ErrMsg)) { return -1; }
         if (redirects[1] && redirects[2] && 
-            *(redirects[1]) != *(redirects[2])) {
+            *(redirects[1]) == *(redirects[2])) {
+          // If stdout and stderr should go to the same place, redirect stderr
+          // to the FD already open for stdout.
+          if (-1 == dup2(1,2)) {
+            MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout");
+            return -1;
+          }
+        } else {
+          // Just redirect stderr
           if (RedirectIO(redirects[2], 2, ErrMsg)) { return -1; }
-        } else if (-1 == dup2(1,2)) {
-          MakeErrMsg(ErrMsg, "Can't redirect");
-          return -1;
         }
       }
 
diff --git a/lib/System/Win32/Program.inc b/lib/System/Win32/Program.inc
index 52eb9677ffb..7e97c7fb4a4 100644
--- a/lib/System/Win32/Program.inc
+++ b/lib/System/Win32/Program.inc
@@ -176,7 +176,14 @@ Program::ExecuteAndWait(const Path& path,
       MakeErrMsg(ErrMsg, "can't redirect stdout");
       return -1;
     }
-    if (redirects[1] && redirects[2] && *(redirects[1]) != *(redirects[2])) {
+    if (redirects[1] && redirects[2] && *(redirects[1]) == *(redirects[2])) {
+      // If stdout and stderr should go to the same place, redirect stderr
+      // to the handle already open for stdout.
+      DuplicateHandle(GetCurrentProcess(), si.hStdOutput,
+                      GetCurrentProcess(), &si.hStdError,
+                      0, TRUE, DUPLICATE_SAME_ACCESS);
+    } else {
+      // Just redirect stderr
       si.hStdError = RedirectIO(redirects[2], 2, ErrMsg);
       if (si.hStdError == INVALID_HANDLE_VALUE) {
         CloseHandle(si.hStdInput);
@@ -184,10 +191,6 @@ Program::ExecuteAndWait(const Path& path,
         MakeErrMsg(ErrMsg, "can't redirect stderr");
         return -1;
       }
-    } else {
-      DuplicateHandle(GetCurrentProcess(), si.hStdOutput,
-                      GetCurrentProcess(), &si.hStdError,
-                      0, TRUE, DUPLICATE_SAME_ACCESS);
     }
   }