Exception: Required parameter theme_dir was not passed

Aug 2, 2017 • Magento2

If you are trying to send an E-Mail in a cronjob or a console command and encounter following error that the required parameter theme_dir was not passed like this:

[InvalidArgumentException]
Required parameter 'theme_dir' was not passed

Try to wrap your code inside an emulateAreaCode call, which fixes this issue.

// @var $appState Magento\Framework\App\State
$appState->emulateAreaCode('frontend', function () {
    // stuff
});