2010

Create a Group Policy to Delete these keys

[-HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Word\Resiliency\DisabledItems]
[-HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Resiliency\DisabledItems]
[-HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Excel\Resiliency\DisabledItems]

2013

The above does not work for 2013 and this key needs to disable mssphtb.dll ( Windows search for Outlook 2010 ) 

You will need to find your Outlook Add In name for the below ( I have used WorksiteEmailManagement.Connect )

If you install the plugin it should be listed in 

HKEY_CURRENT_USER\Software\Microsoft\Office\Outlook\Addins

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 WorkSiteEmailManagement.Connect
5. Double-click the entry to edit it
6. Set the value to 1
7. Close Windows Registry Editor

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\Outlook\Addins\WorkSiteEmailManagement.Connect
3. Using the pane on the right, right-click and from the menu select New, DWORD (32-bit) Value
4. Enter the name as LoadBehavior
5. Double-click the entry to edit it
6. Set the value to 3
7. Close Windows Registry Editor