diff --git a/src/Composer/Downloader/FileDownloader.php b/src/Composer/Downloader/FileDownloader.php
index 4ddd01ca7..356934514 100644
--- a/src/Composer/Downloader/FileDownloader.php
+++ b/src/Composer/Downloader/FileDownloader.php
@@ -101,7 +101,9 @@ class FileDownloader implements DownloaderInterface
      */
     public function remove(PackageInterface $package, $path)
     {
-        $this->filesystem->removeDirectory($path);
+        if (!$this->filesystem->removeDirectory($path)) {
+            throw new \RuntimeException('Could not completely delete '.$path.', aborting.');
+        }
     }
 
     /**
diff --git a/src/Composer/Downloader/VcsDownloader.php b/src/Composer/Downloader/VcsDownloader.php
index 8c264f7bb..2d19bba40 100644
--- a/src/Composer/Downloader/VcsDownloader.php
+++ b/src/Composer/Downloader/VcsDownloader.php
@@ -77,7 +77,9 @@ abstract class VcsDownloader implements DownloaderInterface
     public function remove(PackageInterface $package, $path)
     {
         $this->enforceCleanDirectory($path);
-        $this->filesystem->removeDirectory($path);
+        if (!$this->filesystem->removeDirectory($path)) {
+            throw new \RuntimeException('Could not completely delete '.$path.', aborting.');
+        }
     }
 
     /**
diff --git a/src/Composer/Util/Filesystem.php b/src/Composer/Util/Filesystem.php
index 88e8a77c2..fd60cd2fd 100644
--- a/src/Composer/Util/Filesystem.php
+++ b/src/Composer/Util/Filesystem.php
@@ -34,7 +34,7 @@ class Filesystem
         // clear stat cache because external processes aren't tracked by the php stat cache
         clearstatcache();
 
-        return $result;
+        return $result && !is_dir($directory);
     }
 
     public function ensureDirectoryExists($directory)