Thanks. The problem seems to be that the email does not have a sender,s address, hence the "unknown". It then goes into some kind of loop as it doesn't know who to senf the receipt to. Any ideas?
In Microsoft Outlook I received an email from a friend. When I opened it it requested a receipt request to "unknown" or NULL.
I typed NO and Outlook closed itself.
Later I tried to delete the item permanently but the receipt request was repeated and the item would not delete. I have also tried...