Emails stuck in Outbox - again

Iron Contributor

Lately, I experience more an more customers calling me because Emails are stuck in Outlook's Outbox. 

The problem can be overcome by creating a completely new message, copying the content over and send that message off. All while many other messages went out the Outbox without issues. 


I've had that behavior before now and then over the years and usually "fixed" it by deleting the local .OST file or even creating a new Outlook Profile. This did it for most users, but I now get cases where I had done that "fixing" before already. 


I looked into it once again and found that

  • Emails stuck in Outlooks Outbox are only visible in Outlook. There is no copy of the same message on Office 365 OWA in the same folder.
  • Each of those emails seem also not to appear in the Draft folder in OWA while still editing, although they are visible and editable in Outlook. 
  • All those emails are rather small (1-3k) with no attachments
  • All those emails are replies or forwards of email received in the Inbox (both local and in OWA visible). Never newly created messages.

By the way, SARA ( provides a new function to try to fix issues with sent messages. However, SARA won't find the messages stuck in the Outbox (albeit I can see and open them) in my cases and thus can't fix, apparently. 


What could be the reason of those stuck messages and how can I finally fix that issue?


It occurs across different tenants. The most common denominator seems to be Office 2016, although I've had the problem also with other versions of Outlook. 





11 Replies

@DanHuberI have seen this on several customers. Try with turning off "Download Shared Folder" in:


File-->Account settings-->Account settings...-->Change-->More Settings-->Advanced-->uncheck "Download shared folders"


There has never been one and same solution to this problem, but this one is more "permanent" solution to try.



This temp fix works with a PC restart.  I hate it but here it is : 


Try these on the command prompt - Locate cmd.exe from the start menu - Right Click - Run as administrator.  


netsh winsock reset 

press enter

ipconfig /flushdns 

press enter


Restart your PC. 


Open outlook after restart. Let it connect . Your emails will have gone from the outbox.


@DanHuber - We've hit this twice (sporadically) and of course it's the MD having the issue. When it happens to him, his whole Outlook app becomes unresponsive and both times we haven't been able to recover the emails as the only option was to force a shutdown of Outlook. They don't appear in any of the local folders Sent/Drafts/Outbox and nothing in Mail Flow in the 365 Admin Centre.


I did notice (thanks to @Alan_Shaban) that he did have "Download shared folders" selected on his Outlook client, so I've unselected that and hoping for the best.


Any other suggestions that might help me prevent this time-bomb and save me some angst  would be very much appreciated.


Outlook messages remain stuck in the Outbox and I don;t even receive incoming messages until I restart the computer...then income and outgoing messages get sent. I can;t keep restarting my computer 100 times a day. 

@Brian295You might want to try Office uninstall tool and get a fresh Office start:

Thanks for that. We did end up rebuilding his mail profile and that seems to have fixed the issue.



I've found that forcing a recreate on the data file gets this working. Simply navigate to the file location of the outlook data file and rename the file. I usually add an "_old" at the end. You can then start outlook and it will recreate the data file. Hope this helps.

Yes, that is what I am doing as a last resort. 

The first thing to try is to recreate the email message and copy/paste the content and subject from the failing email message. Then send that one.

That works too, most of the time. 


But those are just workarounds. I was looking for an actual fix :)




I had the same problem in Outlook 2007 and Outlook 2019 and here's how I fixed it.
In Outlook 2019 I did these steps:

Click the FILE menu
Click the YES button, when asked to allow app to make changes
Click the EMAIL ACCOUNTS… button
Click on YOUR EMAIL ADDREESS under NAME then click CHANGE..
Click the MORE SETTINGS… button
Click on the tab OUTGOING SERVER
Then type in your EMAIL ADDRESS and PASSWORD below it
Click OK

That fixed my problem.


@RAJAT_K  Usually work around solution that i will do is by opening outlook in safe mode, send a test mail and the mail will be out from outbox. Close the outlook safe mode and open as normal outlook. Send test mail successful.

@Saran7980 I am now having this same problem. This is the first time I recall ever having it. this is ANNOYING Microsoft. If it happens again, I'll try some of these suggested workarounds.