Sent Emails Sitting in Outbox in Outlook App for Mac

Question

A user in my organization will sometimes experience an issue where a sent email sitting in the Outbox for some time before it is finally sent. This is for the Outlook app for Mac. Outlook on web works fine, although user doesn't use the web version often enough to notice any issues.

I also noticed that the user's Outlook app is using a lot of computer resources on the MacBook Air. At one point, Outlook app had sent over 388 MB over the user's network and over 700MB for memory (compared to Teams 150MB). The user has a new computer and I am guessing that there is a lot of email that needs to be synced on the new laptop.

So my question is - what may be causing the sent emails to sit in the Outbox? Could the large amount of resources that Outlook is using on the machine be from syncing several year's worth of email to the Outlook app? Could that cause some slowness in emails being sent?

Answer 1

Hi @WilliamM ,

A user in my organization will sometimes experience an issue where a sent email sitting in the Outbox for some time before it is finally sent.

For the message itself, did it have a large attachment? If so, it's normal to need more time to send it.

If the message is actually same with others, considering it could be sent finally , I think it may be caused by any performance issues on your Outlook for Mac, so what's the specific version of your Outlook (Outlook>About Outlook), please first ensure that you have updated to the latest version.

I noticed it's a new machine and you are syncing multiple messages from server, based on my research, I found a relevant thread that does mentioned it would slow the synchronization with the mail server and affect the client performance if there are multiple messages in Inbox, in this case, it's recommended to move the messages to your Mac machine. For more information, please refer to it : Mac Outlook slows down

Hope that would be helpful to you.

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Answer 2

Thank you for the help. I met with the user and the issue no longer appears. Since the desktop app was able to successfully sync all the emails from the account on the server, performance of the has improved.

So we believe it to be related to the large amounts of emails being synced causing performance to be affected.