diff --git a/src/Composer/Repository/Vcs/GitDriver.php b/src/Composer/Repository/Vcs/GitDriver.php
index a47643988..ecb92a50b 100644
--- a/src/Composer/Repository/Vcs/GitDriver.php
+++ b/src/Composer/Repository/Vcs/GitDriver.php
@@ -227,7 +227,7 @@ class GitDriver extends VcsDriver
         if (Filesystem::isLocalPath($url)) {
             $url = Filesystem::getPlatformPath($url);
             if (!is_dir($url)) {
-                throw new \RuntimeException('Directory does not exist: '.$url);
+                return false;
             }
 
             $process = new ProcessExecutor($io);
diff --git a/src/Composer/Repository/Vcs/HgDriver.php b/src/Composer/Repository/Vcs/HgDriver.php
index eb962f276..5fd1ef06f 100644
--- a/src/Composer/Repository/Vcs/HgDriver.php
+++ b/src/Composer/Repository/Vcs/HgDriver.php
@@ -200,7 +200,7 @@ class HgDriver extends VcsDriver
         if (Filesystem::isLocalPath($url)) {
             $url = Filesystem::getPlatformPath($url);
             if (!is_dir($url)) {
-                throw new \RuntimeException('Directory does not exist: '.$url);
+                return false;
             }
 
             $process = new ProcessExecutor();