madeyouclickstudio/onesync

OneSync is a free Windows program that lets a school or small organisation use OneDrive and SharePoint as if they were old-fashioned mapped network drives, with letters like H:, I:, and J: showing up in File Explorer. It is aimed at places that want the file-server feel without buying commercial products like Cloud Drive Mapper or ZeeDrive, and that find the standard Microsoft OneDrive sync client awkward for their users. Files appear right away as lightweight placeholders. The actual file contents are only downloaded when a user opens a document, and folder contents are only fetched the first time someone clicks into them. This keeps the first mount cheap even when the library behind it is huge. The author has put a lot of work into being polite to the Microsoft Graph API, with a per-machine rate limit of 30 requests per second sustained and 60 in a burst, automatic respect for any pause requests Microsoft sends back, and a setup that avoids the big folder-walk that other sync clients do at startup. The stated goal is that 200 students all logging in at five to nine in the morning will not flood the tenant. On top of mounting the drives, OneSync adds touches the author missed in other tools. File Explorer shows accurate free-space figures from the real OneDrive quota, image thumbnails render in folders, a tray widget shows live upload progress, and a recycle-bin view lists recently deleted files and links into the web recycle bin to restore them. Installation needs Windows 10 version 1809 or Windows 11 and local administrator rights, because the Dokan user-mode filesystem driver it builds on runs in kernel mode. Three download options are published with each release: a bundled installer, a separate MSI for Intune or Group Policy deployment, and the Dokan driver MSI. The first launch runs a wizard that asks for tenant ID, application ID, and which drives to mount. OneSync is released under the MIT license and is not a Microsoft product.