diff --git a/src/Composer/Util/ProcessExecutor.php b/src/Composer/Util/ProcessExecutor.php
index 68d542134..de26f6fd6 100644
--- a/src/Composer/Util/ProcessExecutor.php
+++ b/src/Composer/Util/ProcessExecutor.php
@@ -106,7 +106,7 @@ class ProcessExecutor
         }
 
         if (Process::ERR === $type) {
-            $this->io->writeError($buffer);
+            $this->io->writeError($buffer, false);
         } else {
             $this->io->write($buffer, false);
         }