• It doesn’t delete them from OneDrive, because they never get uploaded. If you max out the storage on OneDrive, then have a program write to that folder, it looks like everything is fine but OneDrive then deletes it once it notices no space is left.

    It’s anecdotal, but I’ve seen it do this myself.

    Perhaps to clarify: OneDrive folders exist both locally and in the cloud. If OneDrive is full, programs can still write to the local folder (nothing OneDrive can do to prevent that) so they don’t error or anything, but once OneDrive fails to upload the file just goes poof.