diff --git a/src/Composer/Downloader/ArchiveDownloader.php b/src/Composer/Downloader/ArchiveDownloader.php
index 8f7f5ef83..14b434b74 100644
--- a/src/Composer/Downloader/ArchiveDownloader.php
+++ b/src/Composer/Downloader/ArchiveDownloader.php
@@ -29,7 +29,7 @@ abstract class ArchiveDownloader extends FileDownloader
 {
     public function download(PackageInterface $package, $path, PackageInterface $prevPackage = null, $output = true)
     {
-        // if not downgrading and the dir already exists it seems we have an inconsistent state in the vendor dir and the user should fix it
+        // if not upgrading/downgrading and the dir already exists it seems we have an inconsistent state in the vendor dir and the user should fix it
         if (!$prevPackage && is_dir($path) && !$this->filesystem->isDirEmpty($path)) {
             throw new IrrecoverableDownloadException('Expected empty path to extract '.$package.' into but directory exists: '.$path);
         }
diff --git a/src/Composer/Downloader/FileDownloader.php b/src/Composer/Downloader/FileDownloader.php
index b965e62d4..3da51d39b 100644
--- a/src/Composer/Downloader/FileDownloader.php
+++ b/src/Composer/Downloader/FileDownloader.php
@@ -425,6 +425,10 @@ class FileDownloader implements DownloaderInterface, ChangeReportInterface
         $output = '';
 
         try {
+            if (is_dir($targetDir.'_compare')) {
+                $this->filesystem->removeDirectory($targetDir.'_compare');
+            }
+
             $this->download($package, $targetDir.'_compare', null, false);
             $this->httpDownloader->wait();
             $this->install($package, $targetDir.'_compare', false);