I would like to run the rule which upon receiving a specific email would
create a text file and close the script to allow for further operation on
the file.

I thought that something like below in script would work

Sub CustomMailMessageRule(Item As Outlook.MailItem)
       Open "c:\emailtest\test.txt" For Random As #1
   Close file
End Sub

no :-(...any hints would be appreciated

If I do this

Sub CustomMailMessageRule(Item As Outlook.MailItem)
  MsgBox "Mail message arrived: " & Item.Subject
    Open "c:\emailtest\test.txt" For Random As #1
   Close file
End Sub

it displays the message  box , it creates the file, however I need silent
operation
and in this case I cannot acces the file as it remains in use by Outlook