Outlook 2016: POP3 duplicates after installing the February 16 Update

Update:
This issue has been solved in the March 4 update for Office 365, version 16.0.6568.2036. To get this fix directly, in Outlook choose: File-> Office Account-> Update Options-> Update Now. If you’ve previously disabled updates, you’ll first have to choose “Enable Updates”.

After updating, you may receive duplicates from the mail server one last time. To get rid of these duplicates see: Delete duplicates after emails got redownloaded

After applying the February 16 update for Office 365, version 16.0.6568.2025, you may encounter the following issues in Outlook 2016 when you are using a POP3 account.

  • When you have the POP3 account configured to leave the emails on the mail server  for x days, the setting isn’t being respected and all emails are deleted from the mail server anyway.
  • When you have the POP3 account configured to leave all the emails on the mail server, the emails are repeatedly being downloaded and thus cause duplicates.

Microsoft is working on a fix but in the meantime, you can use one of the following workarounds.

For cleanup tips see: Delete duplicates after emails got redownloaded.

Uninstalling the update

Before uninstalling the update, disable automatic update via:
File-> Office Account-> Update Options-> Disable Updates

Additionally, create a reminder in your Calendar to re-enable updates in April as a fix for this issue should be deployed by then.

To uninstall the update and revert to the February 9 build, open a Command Prompt as an Administrator and run the following command:

"C:\Program Files\Common Files\microsoft shared\ClickToRun\OfficeC2RClient.exe" /update user updatetoversion=16.0.6366.2068

If you get an error when trying to revert to this build, revert to the January 25 build instead:

"C:\Program Files\Common Files\microsoft shared\ClickToRun\OfficeC2RClient.exe" /update user updatetoversion=16.0.6366.2062

For more details and screenshots see: Uninstall Office 365 Click-To-Run Updates.