Duplicated emails in Inbox Outlook

Question

Duplicated emails in Inbox Outlook

Saint007 5

Hi, an Office365 user with Business Standard license has a problem in Outlook. For no apparent reason some random emails are duplicated. If one of these emails is read the copy is also read and if it is deleted the copy is also deleted. The only way to resolve this is to close and reopen Outlook and the duplicate emails will disappear. The problem recurs again on other emails after a few weeks. After reinstalling Office and recreating the OST file, we decided to replace the PC but the problem also recurred on the new PC. Has this happened to anyone yet? How did you solve it? The user uses categories a lot other than that there is nothing in particular that could cause the problem.

Thanks for any advice.

Faery Fu-MSFT 19,751 Reputation points Moderator

2023-11-20T06:57:58.7033333+00:00

Hi @Saint007 ，

Have you configured the account as imap or pop account type?

Also check if there is a rule for creating a copy of the message.
Saint007 5 Reputation points

2023-11-20T08:08:18.6233333+00:00

Hi, the configuration is MAPI type. No rules created.
Faery Fu-MSFT 19,751 Reputation points Moderator

2023-11-27T09:19:05.5466667+00:00

Hi @Saint007 ，

Check your rule settings to make sure there are no duplicate or conflicting rules.

Check whether the mailbox is configured on the mobile device. If so, remove the mailbox on the device to see if the problem persists.

Open Outlook in safe mode and see if there are any duplicate emails (press Windows + R keys > enter outlook.exe /safe > click OK).