Microsoft Outlook - Emails wont send/ are stuck in my Outbox!

Relates to: Office 2007, Office 2010, and Office 2013

Unfortunately as great as Microsoft Outlook is (most popular business email client, extremely customizable, seamless integration etc), it does have its “moments”!

One such time is when emails dont seem to want to send! They stay in the Outbox seemingly staying there forever, just trying to resend over and over

To make matters worse, the email recipient often receives your email multiple times, and deleting your email from your outbox can be a nightmare!

The cause?

More often than not, the perpetual email sending and stuck email is caused when a user tries to send more than a 20MB attachment through their privately hosted mail server. This can be either:

  • 1 email with 1 attachment over 20MB
  • 1 email with multiple attachments totally over 20MB
  • Multiple emails sent at once with attachments totaling over 20MB (to be fair, this is pretty rare though and has more to do with server time-outs)

Generally speaking (and to avoid problems!), 20MB is the absolute limit with privately hosted mail servers. (Hosting providers often set their limit at 25MB to avoid these problems, but if your reading this, it’s a safe bet to guess that your provider doesn’t!) In such cases, 20MB doesn’t mean 21MB, it doesnt mean 20.5MB. As mentioned above, 20MB is the absolute limit. Think of it as a truck going into a tunnel at speed along a highway, with the tunnels clearance height being 20 meters. If the height of the truck is 20.5 meters… there is going to be a BIG problem!


Option 1: Zip your attachments. You can even break the Zip into smaller files (eg 2 x 10.2MB) and send each separately

Option 2: Use a cloud solution. Uploading large files to a cloud solution is far more forgiving, and if you use a solution such as DropBox for example, you can just send your recipient a link to the file and they can then download it at their leisure

Option 2 would definitely be our recommendation

What would also help:

Increasing your internet upload speed to avoid server timeouts. This sounds trivial, but if you have a particularly poor internet plan and multiple PC’s Laptops etc all doing updates and/ or streaming – sending a large email attachment is going to be a challenge!

How do I delete emails stuck in my OUTBOX?

To delete an email in your outbox:

  1. Click on the Send/ Receive Tab
  2. Select ‘Work Offline’
  3. Delete the email (plz note, if this doesn’t work, close outlook, open Outlook and try again. If this still doesn’t work, reboot the machine, Open outlook and try deleting again)
  4. Once the email is deleted, go back to the Send/ Receive tab and click “Work Offline” again (which puts your outlook Online so you can start sending emails again)


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