Explanation

You are using the Exclaimer Mail Archiver Outlook Add-In on a computer with Outlook 2013 that has no internet connection. You observe that the Outlook Add-In takes several seconds longer to load and you may see the following dialog from Microsoft Outlook:


Cause

The Exclaimer Mail Archiver Outlook Add-In is digitally signed by Exclaimer to verify its authenticity. This is a requirement for all Add-Ins used with Microsoft Outlook and helps protect users against viruses and unsafe Add-Ins. To verify that the certificate is authentic your computer needs to check that the certificate has not been revoked. This list of revoked certificates is provided online by Microsoft and is periodically downloaded from their Internet site. However, on a computer that does not have an Internet connection this list cannot be updated. Our tests show this causes a significant delay in loading the Add-In. Whilst this delay slows down loading Microsoft Outlook by a few seconds it does not cause any problems to either Microsoft Outlook or the Exclaimer Mail Archiver Outlook Add-In.

Workarounds

As this behaviour is controlled by Microsoft Outlook 2013, we cannot control this delay. We can offer the following workarounds to prevent the error dialog being presented to the user.
If possible, temporarily connect the computer to the Internet. This will automatically download the list of revoked certificates from Microsoft. Upon completion the following event will be recorded in the Windows Application Event Log:
Source CAPI2
Level Information
ID 4112
Detail Successful auto update of disallowed certificate list with effective date: Date
Add the following Registry Key which adds the same behaviour as if the user had chosen "Always enable this add-in" from the dialog shown above:
Warning: These steps involve modifying the Windows Registry. Exclaimer strongly recommend backing up the Windows Registry before making any changes to it.
  1. Launch Windows Registry Editor
  2. Navigate to the following path in the tree on the left: HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Resiliency\DoNotDisableAddinList
  3. Using the pane on the right, right-click and from the menu select New, DWORD (32-bit) Value
  4. Enter the name as Exclaimer.MailArchiver.OutlookAddIn
  5. Double-click the entry to edit it
  6. Set the value to 1
  7. Close Windows Registry Editor

More Information

The following Microsoft TechNet article contains additional technical information about how the certificate revocation process works:
http://technet.microsoft.com/library/ee619754.aspx
Troubleshooting Mail Archiver