When trying to send a secure email in Outlook using the Egress Add-in, you may receive a 'Wrapper is not a mailitem' error message as below. Please see the following fixes:
1. Repair/Reinstall office
Reinstalling office will override any incorrect keys and may resolve the issue once the machine has been restarted.
2. Delete incorrect registry keys (IT Department)
Please navigate to the following location in the registry editor:
Please make a backup of this registry location before making any changes!
Delete the version keys (e.g. 9.5) for any version of Outlook that is not installed on the customer’s machine based on the version table provided below. For example, if you are not using Outlook 2013 then remove the "9.5" entry. If you are not using Outlook 2010 then remove the "9.4" entry.
Outlook 2007 9.3
Outlook 2010 9.4
Outlook 2013 9.5
After this change has been made please restart Outlook and restart the Egress client.