Hi Insiders,

We have a new update for you, build 16.0.6568.2036.

To get the update, click File > Account > Update Options > Update Now.

This update fixes two significant POP3 issues in Outlook 2016:

  1. After Outlook downloads email, all email messages on the server are deleted from the Inbox.
  2. Email messages are downloaded multiple times from Outlook, causing duplicate items.

In addition, we've fixed an issue where Office apps would crash if you attempted to convert a file to PDF using Adobe Acrobat PDFMaker.

Special thanks to Insider Mrs. Richardson for being the first to bring the POP3 issues to our attention!

Source: Announcing Insider build 16.0.6568.2036 for Office 2016 on Windows - Microsoft Community