diff --git a/src/Composer/Util/Filesystem.php b/src/Composer/Util/Filesystem.php
index ca395736f..92e5e0623 100644
--- a/src/Composer/Util/Filesystem.php
+++ b/src/Composer/Util/Filesystem.php
@@ -316,7 +316,7 @@ class Filesystem
         $to = lcfirst($this->normalizePath($to));
 
         if ($directories) {
-            $from .= '/dummy_file';
+            $from = rtrim($from, '/') . '/dummy_file';
         }
 
         if (dirname($from) === dirname($to)) {
diff --git a/tests/Composer/Test/Util/FilesystemTest.php b/tests/Composer/Test/Util/FilesystemTest.php
index 8c86c7896..4607512b6 100644
--- a/tests/Composer/Test/Util/FilesystemTest.php
+++ b/tests/Composer/Test/Util/FilesystemTest.php
@@ -112,6 +112,7 @@ class FilesystemTest extends TestCase
             array('/foo/bar_vendor', '/foo/bar', '../bar', true),
             array('/foo/bar_vendor', '/foo/bar/src', '../bar/src', true),
             array('/foo/bar_vendor/src2', '/foo/bar/src/lib', '../../bar/src/lib', true),
+            array('C:/', 'C:/foo/bar/', "foo/bar", true),
         );
     }