My Outlook keeps sending duplicate emails and also automatically moves certain incoming emails into Trash

Andrew Chidester 0 Reputation points
2026-09-10T17:06:10.7+00:00

My Outlook keeps sending duplicate emails and also automatically moves certain incoming emails into Trash. Please help me fix these problems.

Outlook | Windows | Classic Outlook for Windows | For business

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  1. Chris-D 1,180 Reputation points Independent Advisor
    2026-09-10T17:31:34.7566667+00:00

    Hi Andrew,

    Thank you for sharing the details of your situation.  

    Based on your descriptions, here are some steps you can try: 

    1/ Check whether emails are actually being sent twice (for IMAP accounts)

    • Send a test email to another email address and verify whether the recipient receives two copies of the message or whether duplicate messages appear only in the Sent Items folder.
    • If the recipient receives only one copy but duplicate messages appear in Sent Items, and you are using an IMAP account, both the mail server and Outlook may be saving a copy of the sent message.
    • In Classic Outlook, go to: File > Account Settings > Account Settings... > select the affected account > Change 
    • Check whether there is an option such as Don't save copies of sent items or a similar setting related to sent item synchronization. If available, enable the option, complete the setup, and restart Outlook.

    2/ Review your Inbox rules 

    • In Classic Outlook, go to File > Manage Rules & Alerts and check whether any rule is configured to delete messages or move them to Deleted Items. Temporarily disable any suspicious rules and monitor whether the issue continues.  
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    3/ Check the Ignore Conversation setting 

    • The Ignore Conversation feature can automatically move current and future messages from a specific email thread to Deleted Items. 
    • In Classic Outlook, open the Deleted Items folder, select an affected conversation, and go to Home > Ignore > Stop Ignoring Conversation.  
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    4/ Test Outlook in Safe Mode 

    • Close Classic Outlook, press Windows + R, enter outlook.exe /safe, and select OK. Then test whether the issue still occurs. 
    • If the problem does not occur in Safe Mode, an Outlook add-in may be responsible. Go to File > Options > Add-ins > Manage COM Add-ins > Go, temporarily disable the add-ins, and re-enable them one at a time to identify the affected add-in.  
    • Also check the mailbox through Outlook on the web. If the issue occurs there as well, it may be related to a mailbox rule, setting, or another connected device rather than classic Outlook alone. 

    If recipients are receiving duplicate emails, investigate additional causes such as:

    • Multiple Outlook clients connected to the same mailbox
    • Sending/receiving interruptions causing message resubmission
    • Mailbox rules or server-side forwarding rules
    • Antivirus or email security software scanning outbound mail
    • Add-ins that interact with email sending

    I hope this information is helpful. Should you have any further questions or need additional assistance, please feel free to share them in the comment below. I'm very happy to help.  

    I look forward to hearing your thoughts on this. 

    If the answer is helpful, please click 'Yes' and kindly upvote it.

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  2. AI answer

    2026-09-10T17:06:26.3266667+00:00

    For the duplicate sent emails in classic Outlook for Windows with an IMAP account, the supported workaround is to stop Outlook from saving its own copy of sent items:

    1. In Outlook, go to File > Account Settings > Account Settings.
    2. Select the IMAP account, then choose Change.
    3. Select Don't save copies of sent items.
    4. Select Next, then Done.

    This works around cases where the mail server already creates a Sent Items copy and Outlook uploads another one, which causes duplicates. The unread status on one copy is also controlled by the server.

    For incoming mail being moved automatically to Junk or Unwanted, one documented cause is a Samsung mobile device using the default mail app with entries under Spam addresses. In that case:

    1. On the Samsung device, open the email app.
    2. Press Menu > Settings > General Settings.
    3. Open Spam addresses.
    4. Remove any addresses or domains that should not be there, such as the corporate domain.

    For Outlook.com-style junk filtering, also check whether senders or domains were blocked:

    1. Select Settings.
    2. Go to Mail > Junk email.
    3. Review Blocked senders and domains and remove any address or domain that should not be blocked.

    If mail flow problems continue after these checks, run the classic Outlook troubleshooters. If that does not help, contact support.

    AI-generated content may be incorrect. Read our transparency notes for more information.

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