Emails vanishing Exchange

Does the user have a mobile device connected to the mail server via POP3? The default for POP3 is to remove the message from the server after it downloads it to the phone.

Example:

You send john an email and he receives it in his outlook

John's phone queries his account for new mail via POP3 and downloads a copy to his phone then swiftly removes that message from the server

Now Johns outlook doesn't see the message because it was removed by phone

Other email protocols have an option to remove the message from the server but I have seen this happen over POP3 mostly because the default is to remove the message.

"after typing a quick reply the email"

Im guessing the user is selecting Send on the Reply, then the sent item is vanishing

Or the user is I them middle of typing the reply, hasn't selected Send and the email is vanishing?

That being said, what exactly is vanishing?
Just the Sent Item?
Or the original Email as well?

If we are just referring to Sent items

First thing First - "enabled Cached mode" TURN OFF cached Exchange Mode
We need to make sure we are working directly with the mail items themselves, not copies in an ost.


Now

I may check the users rules.
Note all of them down and their settings
Then open outlook using
Start>Run>Outlook.exe /cleanrules


Now try it

If it doesn't happen now, we know its related to one of the users rules


If its still happening I would also look at the properties for the Mailbox, Inbox, and Sent Items in the users outlook

Look at the auto archive settings
Are they set?
If they are what are the settings

Try turning them off, and testing

They had cached mode off and the mail was disappearing.. turning it on the message stayed (which it will do until the next sync cycle) ..

I'd check for a mobile device that is also connecting to the email account..  One test is while on your computer to change the password.. this will stop the mobile device from syncing.

Thanks I am offsite at the moment I will try these suggestions tonight

To clarify  

The user receivers an email from someone.

In outlook the view is two columns inbox and the message panel on the right.  

If they press reply in the right panel they can type a reply to my message,  

Let's say they type.

Hi mate how are you.

They then do not touch the keyboard or mouse for 2 minutes or less.  This email Vanishes like you would expect if the send button was pressed.  

There is then no trace of this message

POP3 would only look at inbox, this sounds like an IMAP connection.

As stated above this is outlook 2013 connected to exchange on the internal network

Does the user have a mobile device connected to the mail server via POP3? The default for POP3 is to remove the message from the server after it downloads it to the phone.

Yes they do have a mobile device however it is connected via exchange an iphone, no other devices  POP is not in use on this server.


I have not been able to replicate the issue since enabling cached mode on the server.

Look at the auto archive settings
Are they set?
Auto Archive is off.

All I could pin this down to was an addon in outlook as the issue has not occurred since disabling  addons

Thanks for all your help guys