Outlook Not Adding Attachments and Can't Send Emails They All Go To Outbox

Question

Outlook Not Adding Attachments and Can't Send Emails They All Go To Outbox

Murphy, Michael L 5

This started about a week ago. It happened randomly, no new updates or changes on my computer. It has persisted and not gotten any better. When I try to attach something to an email, it fails to attach but does not give any error, it attempts to attach and then when it's done loading there is just no attachment. Also, when I try to send an email it goes to the outbox and there's nothing I can do. Also also, when I read emails on my laptop, it does not sync and those same emails show as unread on my phone and then after restarting the desktop app they show as unread as well. In the old Outlook as well I experience the same problem but worse, my inbox does not update at all. Nothing makes it better, not logging out and logging in, reinstalling, running the troubleshooter.

This happened previously and then all of a sudden it was working again and I didn't do anything to fix it. All other services are running fine, outlook works from my browser, and the Microsoft store works as well and so does backing up my Word to OneDrive. Everything is updated. I am running version 1.2025.702.500, windows 11 24H2

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Answer 1

Dear @Murphy, Michael L

Good day. Thank you for reaching out to Microsoft Q&A Forum. We are happy to help you!

We're sorry that you're having a problem, and from the situation you've encountered, we deeply understand the inconvenience caused and apologize for it.

Based on your description, I understand that you are unable to send emails with attachments.

If the attachment exceeds a certain size limit, it can prevent the email with the attachment from being sent. Therefore, you might consider compressing the email before sending it.

You can refer to this support article: Reduce attachment size to send large files with Outlook

Regarding the emails show as unread, here are some troubleshooting steps:

Check if the Reading Pane is turned off, as emails may not get marked as read when opening them. Click on the View tab. Select Reading Pane and choose either Right or Bottom. Confirm that it’s not set to Off.
Disable Add-ins: Go to File > Options > Add-Ins. At the bottom of the window, select COM Add-ins from the Manage dropdown and click Go. Uncheck all the add-ins listed, then click OK. Restart Outlook and see if the problem persists.
Create a New Outlook Profile: Go to Control Panel > Mail > Show Profiles. Click Add to create a new profile. Set it as default and reconfigure your email account.

If the issue is only related to one unread email, view only unread messages in Outlook: At the top of the message list, above the column headings, are two preset filtering options All and Unread.

I hope it will be fixed. Should you have any further questions, please don’t hesitate to ask. We’re here to assist you as quickly as possible.

Your understanding and co-operation are highly appreciated. Thanks for your precious time. Have a nice day!

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Murphy, Michael L 5 Reputation points

2025-07-23T12:37:23.3933333+00:00

That's not my issue with the attachments. It only doesn't work in the desktop app, it's fine on the phone app and fine online. And that didn't work to fix the unread emails. And you did not address the emails getting stuck in the outbox. How can I just fully reset Outlook. Every way I've tried including repairing, resetting, uninstalling doesn't work; I reinstall the app and I'm already logged in so clearly nothing has done a true reset
Jade Ng 1,720 Reputation points Microsoft External Staff Moderator

2025-07-24T08:08:03.2833333+00:00

Dear @Murphy, Michael L

Thank you for your response.

Based on the information you provided, here are some methods you can try:

1.Delete Outlook Profile

Go to Control Panel > Mail > Show Profiles.

Delete all profiles listed.

Restart your PC.

2.Clear Cached Credentials

Open Credential Manager (Control Panel > Credential Manager > Windows Credentials).

Remove any entries related to Outlook, Office, Microsoft 365, Exchange, etc.

3.Clear Registry Keys (Advanced)

Open regedit and navigate to: *HKEY_CURRENT_USER\Software\Microsoft\Office*

Delete the folder corresponding to your Outlook version (e.g., 16.0 or Outlook).

Note: Back up your registry before making changes.

Please feel free to reply below if you have any update or further concern.

Thank you for your patience and understanding. We appreciate your continued trust.

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Outlook Not Adding Attachments and Can't Send Emails They All Go To Outbox

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