We've been experiencing this 'phenomenon' for several weeks. Randomly, different users believed to have sent email when no email was ever sent. In fact no trace in our Exchange logs either. Each had a random window in which any email sent just disappeared. It never made it to sent items and never made it to our exchange server. All with no Outlook errors and appearing to functioning normally thereafter.

In one case a user had discovered an entire days worth of mail had unknowingly not been sent and was not found in the sent items folder.

These installations are on new machines, Outlook 2013 (o365) and Windows 8.1 with all updates applied. For one it happened on the first day and for others it happened a few weeks later.

Everything I find on the web seems to lead to nowhere because it can't be reproduced and once discovered, if ever discovered at all, it's too late.

Up to now we've only disabled cached mode and are waiting to see if it re-occurs but it will only be when someone actually notices it.

Anyone else seeing this?

Shawn

Hi shawn,

Thank you for your question.

Was email place other folders? For example :Drafts or Junk folder.

Did the outlook has customized folder? We could use outlook.exe /cleanviews in RUN on the client to check if the issue persist.

Notice: The /cleanviews switch will wipe out all custom views and return to all default views.

Please ask for network administrator to make sure network is well without any problems. Because we are thinking IP packet which is missing in network.

We could check if there are virus in organization. Which is on client, Exchange server and other network device.

When this phenomenon happen again, we could check if there are other application logs or event ids on Exchange server.

If there are any questions regarding this issue, please be free to let me know.

Best Regard,

Jim

Hi

As per the information and details provided by you, to solve the issues with Outlook send emails, please follow these steps: -

In Outlook 2013, emails are not send may be because of the following reasons: -

• A message is stuck because it has a large attachment.
• You open a message or view Outlook while emails are waiting to be sent.
• Wrong or changed password for the email account.
• Incorrect settings, account not properly authenticated with the email server.
• Outlook is set to work offline or the mail server is offline.
• No email account is set as default.
• Use of software that accesses Outlook data files (.pst or .ost)
• Antivirus or anti-spam software is scanning your outgoing email.

Enable the Save copies of messages in the Sent Items Folder option by following the steps below for your version of outlook:

1. Click File > Options.
2. In the Outlook Options > Mail.
3. Under the Save Messages section, enable the Save copies of messages in the Sent Items folder option.
4. Click OK.

I hope this information will be helpful for you.

Thanks and regards

Shweta@G 

Hi Jim,

As mentioned in my post, Exchange never received the email. All other mail from the user is processed normally and can be found in Sent Items. Please note this is a random issue and Outlook never indicates there is an issue and functions normally at all other times. 

Shawn

Hi Shweta 

There is no trace in Exchange and Outlook functions normally at all other times. The problem can occur for a few minutes or up to a couple of hours and in one case almost an entire day.

Please note.. There are no messages in the Outbox, Sent Items or Exchange logs.

Thanks,

Shawn