SharingItem.SharingProviderGuid Property (Outlook)
Office 2013
Published: July 16, 2012
Returns a String that represents the GUID of the sharing provider used by the SharingItem object. Read-only.
The GUID is returned as a string using the following format:
{00000000-0000-0000-0000-000000000000}
If the SharingProvider property of the SharingItem object is set to olProviderUnknown, you can use the SharingProviderGUID property to identify the sharing provider.