Not allow move to folder w/o containing certain text in subject line

[SimplyPsyke]

I am looking for some guidance on how to prevent an email from being moved to certain folders without certain text in the subject line. Ideally, adding a prompt to remind people that they need to add that text before moving it.

The problem I'm trying to solve is we have a shared mailbox which folks need to work out of and then move a finished email to a Processed folder. Before they move it to the Processed folder it needs to have the ticket number included. We've noticed a lot of unworked emails getting moved to this Processed folder either intentionally or in error so working to prevent that in an automated way if possible.

Using Outlook 2013

[gmayor]

If you add the following code to the ThisOutlookSession module of the VBA editor, and either restart Outlook (saving the code) or run the macro Application_Startup from the editor, if you move a message to the Processed folder (a sub folder of Inbox) and the text 'Ticket No:' is missing from the subject the user should get a prompt warning that the ticket number is missing and the message is opened to enable it to be edited.

Option Explicit
Private WithEvents Items As Outlook.Items

Private Sub Application_Startup()
Dim olNS As NameSpace
    Set olNS = GetNamespace("MAPI")
    Set Items = olNS.GetDefaultFolder(olFolderInbox).folders("Processed").Items
lbl_Exit:
    Exit Sub
End Sub

Private Sub Items_ItemAdd(ByVal item As Object)
Dim olFolder As Folder
    On Error GoTo ErrorHandler
    If InStr(1, item.Subject, "Ticket No:") = 0 Then
        MsgBox "Add the ticket number to the subject, or move the message back where it came from!"
        item.Display
    End If
lbl_Exit:
    Exit Sub
ErrorHandler:
    MsgBox Err.Number & " - " & Err.Description
    Err.Clear
    GoTo lbl_Exit
End Sub