Thanks I will try that next time he mentions it.

One of our users has switched to using Outlook with IMAP to read his emails.  He also have an Android tablet which is accessing his emails using IMAP at the same time.  Three times now he has reported that His PC running Outlook was not getting incoming emails which did appear on his tablet.  Is there anything I can do in Mercury to address this?

I have a similar setup with emails on my phone and tablet as well as on my PC but I use Pegasus which seems to be absolutely fine!

 Unfortunately my Outlook users have been beguiled by its support for Google calendar and feel that despite its poor address book and Email experience they want to use it. 

I understand that there is a known bug where Outlook deletes an email from the server before downloading (which seems and unlikely IMAP behaviour, more like POP to me) I have checked and some of the emails which are showing up on the android tablet but not on Outlook are certainly still in the Inbox.

You could try temporarily switching on session logging for MercuryI and make a connection from each device. By comparing the two sessions you should be able to see exactly what the difference is.