diff --git a/src/Composer/Command/RequireCommand.php b/src/Composer/Command/RequireCommand.php
index 4a8a47559..b7ee15681 100644
--- a/src/Composer/Command/RequireCommand.php
+++ b/src/Composer/Command/RequireCommand.php
@@ -558,13 +558,15 @@ EOT
                     throw new \RuntimeException('Unable to read '.$this->json->getPath().' contents to update the lock file hash.');
                 }
                 $lockFile = Factory::getLockFile($this->json->getPath());
-                $lockMtime = filemtime($lockFile);
-                $lock = new JsonFile($lockFile);
-                $lockData = $lock->read();
-                $lockData['content-hash'] = Locker::getContentHash($contents);
-                $lock->write($lockData);
-                if (is_int($lockMtime)) {
-                    @touch($lockFile, $lockMtime);
+                if (file_exists($lockFile)) {
+                    $lockMtime = filemtime($lockFile);
+                    $lock = new JsonFile($lockFile);
+                    $lockData = $lock->read();
+                    $lockData['content-hash'] = Locker::getContentHash($contents);
+                    $lock->write($lockData);
+                    if (is_int($lockMtime)) {
+                        @touch($lockFile, $lockMtime);
+                    }
                 }
             }
         }