Duplicate Emails

Question

Hello,

I am having problems with my Outlook email. For some reason, I am getting duplicate emails in my inbox on my MAC computer. Each email is proceeded with a bold email of the same email.

Can you help me resolve this issue?

Thank you

Answer 1

Hi Kent Heaps

I am happy to help you today. From what you described, I understand how confusing it can be to see duplicate emails.

Have you tried Q&A Assist suggestions? In addition, please try the following:

Step 1: Confirm the account is added only once

Duplicate Inbox emails can occur if the same mailbox is added more than once (for example, as both IMAP and another type).

1. In Outlook for Mac, select “Tools” > “Accounts”
2. Check whether the same email address appears more than once
3. If you see duplicates, remove the extra account and restart Outlook

Step 2: Check for Inbox rules (Outlook and webmail)

Rules that copy or redirect messages can silently create duplicates.

1. In Outlook, go to “Tools” > “Rules”
2. Temporarily disable all rules
3. Ask the sender to send a new test email and observe whether duplication continues

Also check your email provider’s webmail (Gmail, Outlook.com, GMX, etc.) for server‑side rules, which Outlook will still sync.

Step 3: Verify the account type (IMAP vs POP)

1. Go to “Tools” > “Accounts”
2. Select the account and confirm whether it is IMAP or POP
3. If the account is set up as POP and used on more than one device, please try converting it to IMAP to support multi‑device access and avoid this issue.

Step 4: Test using Outlook on the web

This helps determine whether the issue is client‑side or server‑side.

• Sign in to your mailbox via https://outlook.live.com
• Check whether duplicate emails appear there as well

Please feel free to let me know how it goes. I truly appreciate your time and understanding.

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Answer 2

Duplicate messages in Outlook for Mac are commonly caused by how the account is configured or how the mail server handles copies of messages.

For IMAP accounts, one frequent cause is that both Outlook and the mail server save their own copy of a message (especially for Sent Items). When this happens, Outlook can show two copies of the same item, and one may appear bold (unread).

To reduce duplicates caused by IMAP sent-message handling in Outlook for Mac:

1. On the Tools menu, select Accounts.
2. Select the IMAP account that shows duplicates.
3. Select Advanced….
4. Open the Folders tab.
5. Select Don’t store a copy of sent messages.
6. Select OK.

This prevents Outlook from creating a second local copy when the server already saves one, which is a known cause of duplicated and sometimes unread (bold) items.

If duplicates are in the Inbox (not Sent Items), also check:

• Account rules (in Outlook or on the provider’s webmail) that might copy or move messages into the Inbox.
• Any additional accounts or aliases that might be delivering the same message twice.

If the issue persists, use the Outlook for Mac guided support tool for send/receive issues and account configuration checks: select Start in the “I can't send or receive messages in Outlook for Mac” article, then follow the prompts.

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References:

• IMAP Sent Messages (Outlook for Mac) duplicated and unread in Sent Items folder
• I can't send or receive messages in Outlook for Mac
• I can't send or receive messages with Outlook for Mac