I had this exact issue on another machine, that after 2.5 hours on the phone with MS support (via Zoom), the solution was to uninstall MS Office 365 and reinstall it. Spent weeks with MS support and he got rather irritated when they told him to disable ADAL. He then started digging into Windows and how modern auth works and came across the above fix.

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I do NOT have this issue with the other laptop, an iPad, a MacBook Pro and tablet. But as soon as i log out and log back in, the plugin desactivates itself and the authentication bug comes back. Get a free trial to explore all the solution’s data protection capabilities. Domain verification issues can also prevent the normal use of the Microsoft Office 365 suite. Organizations value the capabilities that the Microsoft 365 suite provides for shared access and simultaneous file editing for team members.

Common Office 365 Issues and How to Solve Them

For example, items that you delete from SharePoint or Microsoft Teams are retained in the recycle bin for a certain period before permanent deletion. Therefore, you can locate the original files at their primary SharePoint site and restore them from there. You can unintentionally send an important Microsoft 365 item to the recycle bin, especially if you have too many files on your device’s hard drive. Still, the files you send to the recycle bin are not permanently removed.

Synchronization Issues

And it’s random users, not all users experience this in this environment. I’ve been working with MS for weeks now and getting nowhere. We inherited this client and it took us 2 weeks to discover that whoever setup their O365 tenant originally hadn’t enabled Modern Authentication. We enabled it thinking that would fix the problem, but sadly no.

• Check POP3 and SMTP settings for connecting to Microsoft mail servers (addresses of servers, ports, encryption, authentication).
• Always define a recovery email address when configuring your Office 365 account.
• Follow the instructions provided by the assistant to find and resolve Microsoft Office 365 problems.
• As soon as he figured it out he handed the full fix to MS support with all instructions as shown above.
• If you are having a lot of end-user support headache because of Office365 quirkiness… well, it may very well be because this rather critical module is missing.
• The update channel used by Office 365 depends on your Office 365 subscription plan and on configuration.
• Microsoft Support and Recovery Assistant can help you resolve problems with Microsoft Office, Office 365, and Outlook.

Microsoft 365 Issues with the Safari Browser

These add-ins can cause issues such as app crashes or significant performance degradation. Office 365 syncing problems are common for Office Mobile, but sometimes similar issues may occur for Office 365 desktop applications like OneDrive and Outlook. After looking deeper into my problem with my RDS servers, the only solution I found is to run the script of @spiceuser-lijul into a GPO at each user logon.

Additional resources

If you are having a lot of end-user support headache because of Office365 quirkiness… well, it may very well be because this rather critical module is missing. We haven’t identified WHY it is missing for some user Win10 installs and not others yet. OneDrive issues are a separate category of problems with Microsoft 365.

Just today he IM’d me and said "oh yeah, this other issue we have been trying to fix for weeks on end… it was ALSO just resolved because we fixed this". My main concern is that these dialog boxes may return, prompting further user frustration and possibly generating tickets. Speaking of research, I haven’t found much info newer than December 2018. I haven’t opened a ticket with MS Troubleshooting Outlook sync problems yet but I may if my search does not prove fruitful. Once the key is added, and the user restarts Outlook, they receive a legacy authentication dialog box, enter their domain password, and connect to their mailbox without issue. This seems to be our most effective fix, and it’s the one we arrived at after hours of forum digging and web searches.



For all of my Office 365 clients, including my own setup from the Action Pack, Modern Authentication is enabled. I have run into multiple Outlook 2016 installations where the only way to get connected to Outlook is to add EnableADAL and set it to 1. These have been fresh Office 365 Business Premium installations, existing Office 2016 OEM installations, and on my Action Pack installation of Office 2016. We haven’t seen this issue arise when a user is on a machine that was originally imaged with Office 365.