After upgrading directly from 8451 to 8552 we noticed a problem appearing in the MAPI LOGs: millions of exceptions are logged every day (and therefore the daily MAPI.LOG file occupies several GB...), similar to the ones shown below :
08:46:21.350 [{8506F445-57BB-4B68-A8EC-7AED5DC7D62E}:16] Email Property Error: PidTagInstanceKey
Exception: System.InvalidOperationException: L'oggetto nullable deve avere un valore.
in System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
in MailService.Protocols.Properties.RecipientProperties.GetRecipientProperties(String itemType, EmailAddress emailAddress, String recipientType, db_contact_readonly contactGroup, Nullable`1 index)
08:46:21.350 [{8506F445-57BB-4B68-A8EC-7AED5DC7D62E}:16] Email Property Error: PidTagInstanceKey
Exception: System.InvalidOperationException: L'oggetto nullable deve avere un valore.
in System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
in MailService.Protocols.Properties.RecipientProperties.GetRecipientProperties(String itemType, EmailAddress emailAddress, String recipientType, db_contact_readonly contactGroup, Nullable`1 index)
08:46:21.350 [{8506F445-57BB-4B68-A8EC-7AED5DC7D62E}:16] Email Property Error: PidTagInstanceKey
Exception: System.InvalidOperationException: L'oggetto nullable deve avere un valore.
in System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
in MailService.Protocols.Properties.RecipientProperties.GetRecipientProperties(String itemType, EmailAddress emailAddress, String recipientType, db_contact_readonly contactGroup, Nullable`1 index)
08:46:21.350 [{B95DC254-5722-4A23-B7FD-5C37DB594E61}:8] Email Property Error: PidTagInstanceKey
Exception: System.InvalidOperationException: L'oggetto nullable deve avere un valore.
in System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
in MailService.Protocols.Properties.RecipientProperties.GetRecipientProperties(String itemType, EmailAddress emailAddress, String recipientType, db_contact_readonly contactGroup, Nullable`1 index)
We don't know what these exceptions are caused by, but we are sure that before (with the 8451) they weren't there because the LOGs prior to the update do not contain anything like this and are very small...
For your information, MAPI logs are set to "Exceptions Only".