first i use this code for delete the all attachment in outlook
For i = 1 To oMail.Attachments.Count
oMail.Attachments.Remove(i)
Next
i have 4 attachment it remove but i check the oMail.Attachments.Count
it display 2
After i search in stack forum this code
For Each a As outlook.Attachment In oMail.Attachments
a.Delete()
Next
it delete the 1 & 3 attachment but not delete the 2 & 4 attachment