Hi,
You mean Theme’s directory or plugin directory?
If white screen of death comes to WordPress, please use WP_DEBUG https://codex.wordpress.org/WP_DEBUG enable that in wp-config.php and it will show exactly what cause the fatal error.
If that didn’t help, please pass us the FTP and WordPress login, so that we can able to figure out what cause this.
Let us know,
Thanks,
laranz.