A Microsoft file hosting and synchronization service.
I'm having the same issue on my Macbook.
I keep all my OneDrive files downloaded so I still have a offline backup and can easily copy them to an external HDD as well.
Now I just found that all my downloaded onedrive files are duplicated to another folder and taking up twice the space.
They are located in the CloudStorage Folder but also in the Group Containers Folder.
It seems like microsoft is telling you that the files only use the space once, but this is clearly wrong. My 2 TB SSD of my Macbook is nearly full because of this issue.
If microsoft does not fix this, onedrive is useless for me. And no: Setting the files "on demand" is not the solution and not a fix.
I need the files offline. On windows it works just fine.
If you just search the internet for "Onedrive duplicating files on macos" or similar keywords, you find many users with this problem.
I'm worried microsoft will not fix it, because the problem exists for a long time now.
I am thinking about paying the higher price and switching to iCloud. But therefor i'm unsure about how good icloud works on windows and android as I use a mix of all operating systems. But be aware: OneDrive on MacOs is the worst!