Outlook message disappearing in Outlook 2013

Are they perhaps disappearing from the unread mail folder as opposed to the inbox?  Can you verify that it is actually the inbox you are viewing the message in when it disappears?

Sorry, after re-reading it, are you actually saying that the message still exists but the original text from the message is gone, showing you a blank email?

If this latter is the case, are you using AVG?  I have heard AVG and maybe a few other anti-virus programs have been known to do something of this nature for some messages..  It hits the exchange server fine, hits the outlook client fine, then it purges the text once the AV sees the message.

If so, File > Options > Addins

Com-Addins

Try disabling the antivirus addin and have the sender resend.

Yes the message still exists and the orignal text is gone. No we aren't using AVG. We are using Kaspersky as we are on 24 identical machines with virtually identical setups. As far as I can tell this is happening on two systems only. I have tried to duplicate the problem on my machine with no success.

Can you try disabling kaspersky and having the same message resent or any message that has an issue?  I would just like to eliminate AV as a solution.

Easy way to rule out addins is to run Outlook in safe mode (either by holding the CTRL key while clicking the icon, or by typing "outlook /safe" in the search box) and see if you can reproduce the issue.