A Microsoft file hosting and synchronization service.
Same issue. Just occurred today, after working for 8+ years. I have a family folder that my wife and I share ALL our personal details in.
This morning the sidebar link in my finder said "original location of folder not found", and I couldn't find the folder in the OneDrive location either. I went through all the steps I could find online, from updating, uninstalling, restarting, unlinking, doing the "show package contents", and even going so far as to have her remove sharing of the folder and resharing it.
Just restating, this issue just occurred for me TODAY, Feb 25th, 2025. I'm on the Mac Sequoia 15.3.1, and the most recent version of the standalone OneDrive app.
Quite frankly, disastrous for workflow and efficiency. Very disappointed in Microsoft for this issue persisting for such a long time with no resolution (over 9 months since it was reported?!).