diff --git a/src/Composer/Installer/InstallationManager.php b/src/Composer/Installer/InstallationManager.php
index bde96e73a..698b4f995 100644
--- a/src/Composer/Installer/InstallationManager.php
+++ b/src/Composer/Installer/InstallationManager.php
@@ -464,7 +464,7 @@ class InstallationManager
         if ($progress) {
             $progress->clear();
             // ProgressBar in non-decorated output does not output a final line-break and clear() does nothing
-            if ($this->io->isDecorated()) {
+            if (!$this->io->isDecorated()) {
                 $this->io->writeError('');
             }
         }