Outlook 2016 doesn't accept password or app password

I did report it and feedback refers to several URLs including this one... as known issue.

I can not necessarily speak to any different third-party email applications since I personally don't use them deeply or work on their product teams. However, I can speak to Outlook. You should be able to continue to use any Outlook client that has multiple folders and mail in all of them and be able to sync quickly.

For any other third party client, IMAP is the main protocol and the standard that many email services use to sync.

So no more Exchange for free personal accounts??

The reason I've been using Exchange in all email clients is because IMAP is painfully slow when it comes to syncing all my subfolders which are more than 100.. And syncing inbox only is not an option since I have many rules applied.

Some security "enhancements" seem to defeat basic functionality.
Let's stop using email altogether, it's the safest option for sure..
Would be nice to have an advanced option to use less secure accounts and be responsible for keeping our passwords and devices safe.

In any case the ultimate simple question,
Is there a way I can use a microsoft email containing many subfolders and rules without having to wait 5 minutes to sync???(In any third party email client)

Thanks David for your answers as you are the only person from Microsoft that does it and for sure this is more than needed.

The problem is that nowadays I have different Outlook clients (desktop + mobile) that are not anymore able to sync with my Microsoft accounts (Hotmail and Outlook) due to this OAuth activation. This means that since that date, all my emails, calendar entries and contacts are not anymore updated in those clients and this has created a lot of confusion in my daily life (I had some critical calendar entries that are not anymore synchronized in all my devices, so this made me lose some important appointments).

Furthermore, this is even more painful because in my case, those software clients cannot be upgraded to support OAuth, and for this reason it is really a shame that Microsoft has done a so drastic change without informing us previously, in order to have had enough time to look for some alternative solution.

With so many impacted customers, it would have been better to allow us to decide if we do want to enable OAuth in our Microsoft accounts meanwhile we upgrade our clients or we look for some alternative solution. Unfortunately, Microsoft has activated this OAuth by force to our accounts and it seems that we cannot roll back to the Basic authentication (I just looked some way to disable it but there is no option at all to do it).

Is it really not possible to disable temporally this OAuth feature in our impacted Microsoft accounts?

I keep reading in these posts about OAuth and I haven't the foggiest idea what that is.

OAuth is a modern authentication method of how cloud systems verify who you are and you are the "real you." Because of the constant hacking and that our passwords may be leaked, there is a chance hacker may already have your password. This lead to 2FA or MFA (2 factor or multi-factor authentication). Things like send a SMS message of a pin, email you a pin, or have you enter a one-time code from a security app, are those additional factors of authenticating you.

OAuth provides a mechanism to allow the initial login to handle 2FA/MFA. Some of the older apps were build before OAuth was fully finalized or implemented, so their support OAuth is either partial or missing altogether. OAuth allows a more secured method of storing information that your device or your app is authenticated or trusted, so your app or client doesn't get constantly challenged by the server everytime it tries to fetch or sync data, which happens dozens if not hundreds times a day.

The issue is not OAuth itself but Microsoft's implementation of it on their servers. To be fair, Microsoft is one of the biggest hacking targets in the world, so what it deals with on a daily basis is likely severe and more than what we can appreciate or fully grasp. Microsoft issue is that it made all these changes, unverified, on real-world production servers and yet doesn't offer a comparable method for us to workaround these issues.