My co-worker recently installed Office 2013 64-bit on his Windows 7 (x64-bit) laptop. He installed the Outlook 10.0.4 CHF3 add-in and it is not showing up. Here is a list of troubleshooting steps that we've tried.
-Uninstalling/Reinstalling (running as Admin)
-Checked to make sure Valkyrie.dll was in the EVClient folder and it was.
-log off/log on and a reboot.
I know that last year I had this issue, but I was working on so many other projects that I put it on the backburner and I remember it just showing up one day.
Do you have a copy of the Client Trace?
If you go to Start -> Run -> "Temp" and press OK and look for a file called ev_client_log_datetime.txt
In there it should give some information as to why its not displaying.
It could be that it has Outlook Anywhere (RPC Over HTTP) enabled and the Desktop Policy is set to disable the client (which is the default setting)
It could also be that the default delivery location is set to a PST file and not the main root of the mailbox.
It could be that the hidden message hasn't sync'd down to the OST file and the hidden message can't be read.
It could also be that in the Add-Ins section that the add in has been disabled, you just need to re-enable it and restart Outlook and see if that works
Another thing I have seen fix this issue (as long as you have a sound Enterprise Vault configuration) is to run a "repair" on the Office installation. I would uninstall the Enterprise Vault plugin, run a repair on the Office 2013 installation, reboot, and then re-install the Enterprise Vault plugin.