Fatal error: Uncaught Error: Class "Symfony\Component\Console\Descriptor\Descriptor" not found in C:\mywamp\sites\allsite\calcomposer\vendor\symfony\console\Descriptor\MarkdownDescriptor.php:29 Stack trace: #0 {main} thrown in C:\mywamp\sites\allsite\calcomposer\vendor\symfony\console\Descriptor\MarkdownDescriptor.php on line 29