It works - but only for a few days then problem restarts even though I have made no changes to the password

Just to report that the annoying message still appears but have noticed that when I switch to the settings window the word "verify" briefly appears then disappears. So part of my computer thinks it needs a credential while another part knows it doesn't.

Haven't yet tried signing into another identity.

Thanks for a very direct answer to something MS Techs just spent an hour and never got around to covering. My concerns are the possible consequences of doing this and if there are none it solves my problem.
At some point in the past I have somehow manged to create a Personal MS account with the same login as my Work account.
And being they are the same, I appear I am now logged in as Personal for some time. The system I am on "says" it is also on a Local Account using my login. The problem is that I cannot install the deployment tools for the "next Generation" Sync for Business One Drive unless I connect to Office using my Business account. I am not even sure how office is running at all since as a "Personal account" I do not have access to Office 365 Small Business, it is tied in with my Business email account.

What worries me most is that this system acts as a "shared storage" for many people in the office who are all connected to it via "Local Accounts" over a small office network and I am concerned that these shares may be connected in some way to my profile. If I change it to where it should be using the correct logins to make it a Business account, will that in any way disconnect all those other local users?
Thanks for always having all the right answers!

Thanks very much!

I had also noticed posted a method of disabling the Windows 10 credentials manager as well as posts alluding that the manager itself can cause issues. On looking all the stored credentials on this system, I could how that might happen!

Would you happen to know whether there is anything gained from logging in with a "Microsoft" account (whether Personal or Business) vs using a "Local Account" ?

I ask this because at this office many of these systems were once windows 7. When they upgraded there was a lot of confusion about the difference between Local accounts vs Microsoft accounts to log into their laptop as either seemed to work with no problems. This only got worse when we discovered that we fell into a 3rd category ( Work ) which is a "type of" Microsoft account but one purchased through a Microsoft Partner.

When Windows 10 asked Users to sign-in to Windows using their Microsoft account everyone assumed it was the same as their Work Account used for Office 365. Those who did this found that it worked but required them to create a different password than the one used with their "Business Office 365" account.

When they did this, it created a Free "Personal" account such as I mentioned here. Once this became obvious I was concerned about how to "fix" the confusion without losing the "network". Your solution worked and was appreciated!

I have tried multiple methods for fixing this. Unfortunately, nothing sticks. I've even tried multiple MS accounts, but eventually it will still come back asking for the credentials. I haven't changed anything, so it has no rhyme or reason to it.

At a certain point, I even had reinstalled the OS completely, (Not to fix this, but some other issue) and it eventually still did this. Anyway, how I've resolved this for the most part is by creating a local Admin account. It appears I can still connect to the store using the MS account...Download & install apps or updates. Then logging back out of that account in the store.

The only problem I still see is the native email/calendar app will, for some unknown reason, need to have the account settings "fixed" You click on "Fix.." then it takes about 30 seconds or so & then baam, it's fixed!! I believe that problem is still related to the account or OS. One of my accounts that it needs to be fixed is a gmail account. So, it isn't just because of a outlook account. It's got to be a MS account issue or OS problem.

Any thoughts on fixing this?