After installing FP7 customers complained attachments shows up in both the body field and in the header like a V2 attachment when they used Send to mail recipient from the Windows Explorer menu.
We have tested it, and this occurs with FP7, when rollback to FP6 the send to mail recipient is working like it should.
When sending mail created using Send to mail recipient with FP7 installed to external mail recipients, the mail size is also twice the size.
It seems to have a $File attachment and also the attachment stored as mime in the body.
We have customers reported this using Windows 7, 8.1, 10 and Windows 2012 (RDS).