A client of ours has the latest version of Office 2016 installed. The Outlook version is 16.0.6568.2036
The user has been having issues when sending attachments. It's an intermittent issue, sometimes it happens, sometimes it doesn't.
The user attaches an attachment to an email and sends it to a recipient. The paperclip to suggest there's an attachment on the email is shown but when she opens the email from within the sent box there is no attachment. The recipient hasn't received the attachment either.
The user would then create a new email with the same attachment and the same recipient and it sends fine.
I've checked the mail logs in Exchange 2010 and the server doesn't receive the attachment. (The email is too small)
I've disabled all the addons within Outlook and turned off the Antivirus on the machine. Doesn't fix the issue.
Looking in the OWA the email shows as not having an attachment but again within Outlook 2016 it does.
I've ran a repair on Office and made sure all the updates for both Windows and Office are installed. Only this one user is affected within the organisation.
To clarify the Outlook is configured to use a local (on-premise) Exchange 2010 server. The PC is on a local Domain.