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Microsoft 365
Formerly Office 365, is a line of subscription services offered by Microsoft which adds to and includes the Microsoft Office product line.
4,745 questions
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Hello @O365 Buddy ,
It sounds like you are experiencing an issue with Exchange Online Advanced Threat Protection's dynamic delivery feature causing duplicate attachments. To troubleshoot, may I know if this problem occurs with all attachments or only with certain types of attachments?
Multiple customers have reported duplicate attachments, which may also be caused by the email server or email client being used. Currently, it seems that no users have reported this problem related to ATP. If you speculate it is caused by ATP, a possible solution is to disable the dynamic delivery function. For example, try changing the safe attachment policy to "Block" and view duplicate attachments problem if still exist. If not, the problem may be related to dynamic delivery. Another solution is to check if there are any third-party applications or services that may interfere with dynamic delivery. You could try disabling any such apps or services to see if that resolves the issue. More information for your reference：https://practical365.com/advanced-threat-protection-notes-field/（Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)
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