This is not a NetDocuments issue, but it does affect NetDocuments users.
When you open up an old email in NetDocuments, you can reopen it in Outlook. This is great because you can use Outlook to reply to or forward the email. The problem is that some of those emails will stay in my inbox in the last couple of months. Completely random but very frustrating.
My friend Tony Foy at https://peregrinecloud.com/ finally gave me the solution. In Outlook, disable the Adobe Plugins. This will stop this issue from happening.
I don’t use any of the Adobe features in Outlook, so this is an easy solution.
In Outlook: File –> Options –> Addins –> Com Addins
Once I disabled the Adobe Plugins, I never had this issue again.