Outlook 2016 prompting for login credentials when opening any email attachments

Problem: Outlook 2016 prompting for login credentials when opening any email attachments

After a recent microsofdt update early this Month (October 2017) various bugs have appeared in Outlook 2016 but mostly noticeable the prompt for password for exchange users when opening attachments.
Microsoft is currently working on a patch for this issue.


User gets a prompt for password some seconds after opening an attachment. if you cancel it it may not promptyou again until you open another ttachment. if you enter your password, you will get prompted again.

issue has been documented in Microsoft oficial site:

view list of releases here:

presumed bad update:

September 18, 2017

Version 1708 (Build 8431.2079)



The only recommened solution at this time is to kepp your outlook or Office product up to date by running windows updates.

Alternatively, revert back to a previous update, and disable windows updates.

open command prompt with admin rights.
cd %programfiles%\Common Files\Microsoft Shared\ClickToRun\
then type:
officec2rclient.exe /update user updatetoversion=16.0.8326.2107

to disable windows updates(but you will need to be aware that this can potentially put your system at risk, so this should be done only temporarily if you really need to, but at your own risk)

or another option is to:
If you setup two-step verification on your account you will need to create an App Password to add the account in Outlook.

reference Thread in Microsoft:




• Microsoft Exchange 2010, Office 365, Outlook 2016

courtesy of VND
by Javier Oblitas
http://www.vndx.com Web Solutions and custom programming including Managed Hosting Solutions
http://www.netservers.com custom Hosting...introducing fast Solid State Hosting where everything is possible!

  • Outlook 2016, Password prompt, bug, login popup, office 365
  • 2 Users Found This Useful
Was this answer helpful?

Related Articles

Not able to search in Outlook Web App (OWA)

Problem: cannot search in outlook web App owa in exchange 2010 A user reported they were trying...