A Microsoft file hosting and synchronization service.
This is not a solution for all, but if you are a more advanced user and familiar with terminal, I have forgone the OneDrive app completely and am now using rclone.
I was having the same issues as above - all files were supposed to be on the cloud but after erasing my mac completely two times over, i'd had it with onedrive. It still said my "online" files were taking up 82GB.
Do NOT do this if you aren't familiar with terminal/rsync/rclone or are not an advanced mac user, and read the documentation carefully before running a command so you don't lose any files.
i don't have the energy to get into it all but what i did:
1. install homebrew if you don't have it already
4. execute a rclone sync command
i used the below command, but as I said above - look at the documentation first to make sure it's right for your needs and doesn't delete anything you don't want deleted!
rclone sync /home/user/documents/ myonedriveremote:Documents --progress
works like a charm and is ultimately way more customizable. This is also great if you want to back up your OneDrive to an external disk.
Ps: not sure why the text justification is off in this post so sorry if it’s hard to read!