A Microsoft file hosting and synchronization service.
I am having the same issue, and it cripples my office PC from doing NECESSARY tasks, like being able to save scanned local documents into the shared cloud folder. I can no longer view and print critical work documents in the medical office where the File Explorer is used to access the main office remotely. It now opens Word docs in a browser and skews everything all over.
This is a terrible issue.
This should be updated to an extremely HIGH priority issue to be fixed.