|With Category-Manager you can group your Outlook categories, share them with other users, filter a folder by category, automatically categorize new emails, and more. You can use the Addin even for IMAP.
Paste the code into the 'ThisOutlookSession' module and restart Outlook. As soon as you add a new attachment to an email its name will be displayed as the subject of the message.
Private WithEvents Mail As Outlook.MailItem
Private WithEvents Inspectors As Outlook.Inspectors
Private Sub Application_Startup()
Set Inspectors = Application.Inspectors
Private Sub Inspectors_NewInspector(ByVal Inspector As Inspector)
If TypeOf Inspector.CurrentItem Is Outlook.MailItem Then
Set Mail = Inspector.CurrentItem
Private Sub Mail_AttachmentAdd(ByVal Attachment As Attachment)
Mail.Subject = Attachment.DisplayName