Share via

Outlook (New) on Mac – Replies in Thread Fail to Send and End Up in Drafts

Søren Røisæth 30 Reputation points
2025-11-13T09:16:02.83+00:00

I'm encountering a persistent issue with a user running Outlook (New) on macOS. When she replies to an email within a thread, the message fails to send and ends up in Drafts. This happens consistently and is critical because threaded replies are required in her workflow.

Context:

  • Platform: macOS (latest version)
  • Message Trace: Replies that fail do not appear in Exchange Admin Center trace – indicating they never leave the client
  • Classic Outlook: Not an option due to prior issues
  • Workaround: Replies work when using Outlook Web App (OWA), but the user prefers the desktop client

What we've tried:

  • Previously used a workaround by replying outside the thread – no longer viable
  • Verified that replies work in OWA

Questions:

  • Is this a known issue with Outlook (New) on Mac?
  • Are there any fixes or configuration changes that can resolve this?

Any insights or similar experiences would be greatly appreciated!

User's imageUser's image

Outlook | MacOS | New Outlook for Mac | For business
0 comments
Answer accepted by question author
  1. Jayden-P 12,855 Reputation points Microsoft External Staff Moderator
    2025-11-13T09:59:10.0366667+00:00

    Hi @Søren Røisæth

    Thank you for posting your question in the Microsoft Q&A forum.

    I'm so sorry about this inconvenience that you are facing, I know this affects your workflow a lot.

    Since you are able to send emails on Outlook Web, the problem likely comes from Outlook for Mac.

    Can you confirm if she is still able to send emails normally, not with in the thread or she cannot send emails at all?

    I tested on my side, and I can send emails replies with in a conversation. I'm using version 16.103.

    So first, let's try update your Outlook client by choosing Help > Check for updates.

    Or you can install directly via Update history for Office for Mac - Office release notes | Microsoft Learn.

    User's image

    If the issue still persists, try resetting her account. Clear the cache in Outlook for Mac - Microsoft Support

    Please try and let me know if it works for you.

    I look forward for your reply.

    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".   

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

1 additional answer

Sort by: Most helpful
Most helpful Newest Oldest
  1. OB365 0 Reputation points
    2025-12-11T13:30:07.42+00:00

    I'm interested in knowing whether this issue was ever resolved, as I didn't find a solution while assisting a Mac user experiencing the same problem and error message. The only difference is that unsuccessful replies were placed in the Outbox rather than Drafts. This occurred only when replying to existing email threads.

    As a workaround emails could be sent by switching to OWA or Outlook Mobile to send messages stuck in the Outbox.

Your answer

Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem.