E-mail downtime during conversion of Azure domain from federated to managed?, will client connectivity be effected during this transition?

Hello Experts. Will there be downtime for E-mail when converting a domain in Azure from federated domain to manged domain using Pass-through sync, with Modern auth enabled? We have ADFS 3.0, with centralized mailflow. and I would like to start converting some of the domains in Azure to managed. I know its just a few powershell commands to get this done, but how long does this transition take?, and will the users Outlook client still be able to connect to Exchange Online, will OWA still work during this transition. Please let me know and thanks in advance.
Newguy 123Asked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Vasil Michev (MVP)Commented:
Depends on what you understand by downtime. There might be some downtime for users trying to login to their mailboxes depending on how fast you perform the conversion, but the actual mail flow will not be interrupted. If you have managed AD FS via AAD Connect, you can use the AAD Connect setup wizard to run the conversion, and it will generally be easier/faster. Otherwise, you have to manually convert the domain, convert all users, configure PTA. Optionally you might also configure and run password sync at least once, so that the on-prem passwords are synced to Office 365, but in general with PTA you should need to use the cloud password anymore.

If you schedule it outside of working hours or over the weekend, nobody will probably notice a thing, apart from being prompted for credentials once they get back in the office.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.