diff --git a/bazaar/SysExec/SysExec.cpp b/bazaar/SysExec/SysExec.cpp
index c89ec5c8b..609753fef 100644
--- a/bazaar/SysExec/SysExec.cpp
+++ b/bazaar/SysExec/SysExec.cpp
@@ -89,8 +89,10 @@ bool SysExec(String const &command, String const &args, const VectorMap<String,
 	fflush(stderr);
 
 	// restores stdout and stderr handles
-	dup2(saveStdout, 1);
-	dup2(saveStderr, 2);
+	if(saveStdout != -1)
+		dup2(saveStdout, 1);
+	if(saveStderr != -1)
+		dup2(saveStderr, 2);
 
 	if (result == -1)
 		Cerr() << "Error spawning process\n";