When you delete an email account, this new feature will give you the option to have DA search through your forwarder values (not the forwarder names) and remove these deleted emails, so that any emails sent to the existing forwarders don't cause bounces. For example, say you have two forwarders: one -> email@example.com two -> firstname.lastname@example.org, email@example.com and you also have the email account: firstname.lastname@example.org When you delete the email@example.com email address, when the 'Clean Forwarders Values' checkbox is selected, DA will go through all of your forwarders, and turn them into: one -> :fail: two -> firstname.lastname@example.org so that any emails to one@ or two@ don't cause bounces. Of course, you'll note that the forwader that only had the 1 email becomes a :fail: forwarder. This is just to remind you of what DA just did. Sending an email to one@ will reject the email (but won't generate a bounce if it's being sent to from an external email). This is the best we can do, considering you've just deleted it's destination. DA will also log to the system.log about the action that was done. The default internal directadmin.conf value is: clean_forwarders_on_email_delete=1 if you don't want to offer this option to your clients, set: clean_forwarders_on_email_delete=0 and restart DA. The checkbox value passed with pop deletions (CMD_EMAIL_POP or CMD_API_POP) is: clean_forwarders=yes without this checkbox value being passed, the "clean" won't happen.