A Microsoft file hosting and synchronization service.
I've spent the past week trying to solve this on my Mac. I spent a few days on my own doing everything I could think of, and a few days with tech support over email, redoing all the things I already thought of. I even took the time to do a clean install of Sonoma to see if that resolved it. It did not. The app simply crashed every time it ran and tried to sync. Even with older versions of OneDrive, which I could run by deleting the updater script in LaunchAgent before it ran. The solution... I deleted everything in my OneDrive from the web portal and the app stopped crashing. Now I'm adding files back a few at a time. Fingers crossed!