UPDATE: This temporary fix is no longer required and has been since resolved by the SmarterTools developers.
SmarterTools has updated us on the IMAP issue with Outlook 2016 and the issue is related to changes made to Outlook's IMAP protocol and how it handles deleting emails. The fix is as simple as enabling a single option as shown below.
Follow the steps provided below to resolve the IMAP issues with deleting emails...
If you continue having issues deleting emails, please let us know by opening a support ticket.
Trouble logging in? Simply enter your email address OR username in order to reset your password.
For faster and more reliable delivery, add firstname.lastname@example.org to your trusted senders list in your email software.