A Microsoft file hosting and synchronization service.
Thank you for this, it worked and it didn't.
On my W10 laptop this seems to have reverted to proper 2FA via the MS Authenticator App. I repeated the process on my W11 laptop, and the first time I tried to open the vault it used that slightly different method of 2FA where it uses the app, but displays a code for you to be certain it's the same request. The W10 machine did the same. I authorised it and all was good. However, after a single reboot the W11 laptop reverted to Fingerprint/PIN for the 2FA.
This rather repeated what I seen previously, when I removed both OneDrive for Business and OneDrive Personal. Reinstalled OneDrive personal and all works well. Repeated reboots and 2FA continued to work properly. But as soon as OneDrive for Business is added to this W11 laptop the OneDrive personal reverts to fingerprint/PIN.
Once OD business is installed any attempt tot get to the setting of OD personal causes the system try icon to disappear, I assume it's crashed in the background. If via file explorer or any other app like Word or Excel I attempt to access the files on the OD personal all is fine, it's just the System Tray access that has disappeared. Once restarted you can often get access at the second attempt.
All in all this has become very flaky and with less sense of security and expectation all is well.