Stop Office BACKUP THIS DOCUMENT prompt

Interesting. Are you logged into office with a different personal account to the onedrive app? I've found that can cause a problem. On another machine, I'm logged into office with a business subscription but the onedrive account is a personal account and I don't get that issue.

Purely out of interest, could you try what I suggested by postponing the onedrive syncing (or exiting the app altogether) and see if you still get the same banner?

The strange thing in my case, is that ...

• I am logged on with my Microsoft account across the board (Windows, Office, *OneDrive—*all legal licenses under the same account).
• I am using OneDrive and all the folders are being backed-up/replicated to OneDrive (1TB, part of of Office365 license).
• The files I am opening are on the OneDrive backed-up folders (usually under "Documents"), not elsewhere.

Yet, I still receive the annoying message.

Excel and Word keep displaying a banner when I open a file "BACKUP THIS DOCUMENT - Access this file anywhere with OneDrive included in your subscription"

I have a backup system I use that I like and I don't need OneDrive to backup my files. How do I get OneDrive/Office 365/Windows to stop giving me this prompt?

I click the "X" or Schedule Backup Later to make the banner go away, but it just comes back a little while later. I've opened up the OneDrive app from the system tray and unselected everything from the OneDrive backup, but none of this helps and the prompt keeps coming back.

How do I get this to stop?

It always astounds me when developers think they know more about the users requirements than the users themselves! It's totally senseless that even when you're not logged on in the office 2019 app, it still tries to force you to upload the file to onedrive!

The only way I have found of stopping this annoying idiotic banner is by pausing or stopping the Onedrive Sync or exiting the onedrive app altogether.Then I open the file from the local folder.

Once I'm done, I restart the syncing of onedrive and dropbox (from the app not office).

Ah, I see it now. Had ignored all the strikethrough. Thanks.

Is this not a Message Bar issue?
Options / Trust Center / Message Bar
Deselect [ ] Show Policy Tip in the Message Bar.
Worked for me. (We'll see for how long.)

No, the message is not implemented as a "Policy Tip", so that setting has no effect. That was tried on page 4 of this thread -- and did not work.