This was an odd one that came up during a recent project. My colleague Kevin had activated our standard Keystone workflow email notifications and configured the SMTP settings for the Sitecore application.

A short workflow test later and not only were emails not going out but an error was occurring with the message: “The device is not ready”. What is going on? Why is an IO error being thrown?

Upon investigation, I found some .NET SMTP settings had been added to the Sitecore Web.config. Specifically, a specifiedPickupDirectory setting.

<configuration>
  <system.net>
    <mailSettings>
      <smtp deliveryMethod="specifiedPickupDirectory">
        <specifiedPickupDirectory
          pickupDirectoryLocation="c:\maildrop"
        />
      </smtp>
    </mailSettings>
  </system.net>
</configuration>

In all my years I had never seen anybody configure SMTP to drop messages to the file system for processing. I didn’t even know the SMTP client could be configured this way!

The error occurs if the value specified for the pickupDirectoryLocation property cannot be accessed. In our scenario, it was referencing a drive which did not exist on the system, hence the error.

The fix is pretty easy…

1. Send SMTP directly, not using this setting, OR
2. Make sure the setting is a valid path