Fix Box Authentication Errors When Mounting — NetDrive

A Box drive that mounted fine for weeks suddenly shows a red error indicator, or clicking Mount just spins and times out. Box connects to NetDrive through OAuth 2.0, and unlike a browser session that silently refreshes in the background, a revoked or expired token leaves the drive stuck until you re-authorize it by hand. This walks through the two most common causes and the fix for each.

Mount Box on Windows or macOS with NetDrive

NetDrive lets Google Drive, OneDrive, S3, SFTP, WebDAV and more appear as native drives on Windows and macOS — no syncing, no full downloads.

• Mounts as a native drive letter on Windows or a volume on macOS
• OAuth authorization through the official Box API — no password stored in plain text
• Works alongside your other cloud drives in one drive manager

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Why the Box Connection Breaks

NetDrive authorizes against Box using OAuth 2.0: the first time you set up the drive, a browser window opens, you sign in to Box and grant access, and Box returns an access token that NetDrive stores and presents on every later connection. That token stops working for a handful of specific reasons:

• Manual app revocation. If you (or a Box admin) opened Box’s Account Settings → Apps page and removed NetDrive from the authorized apps list, the token is invalidated immediately.
• Enterprise app approval policy. Box enterprise accounts can restrict which third-party OAuth apps are allowed to connect at all. If your Box admin has not explicitly approved NetDrive, the authorization step can succeed once and then get silently blocked on renewal.
• Password or security event. A Box password change, or Box detecting a login from an unfamiliar location, can force a re-authentication across every connected app, NetDrive included.
• Session or scope expiry. Long-lived tokens still expire eventually. If the drive has been idle for a long stretch, the stored token may simply be too old to use.

Step 1 — Confirm It’s an Auth Problem, Not a Network One

Open NetDrive’s drive manager and look at the Box entry. An authentication failure shows the drive as disconnected or in an error state rather than simply slow to mount. Before touching the token, check whether your other mounted drives are also failing — if Google Drive or S3 are timing out too, the problem is your network or a Box service outage, not the Box authorization itself. If only the Box drive is affected and the error text mentions authentication, authorization, or credentials, move on to Step 2.

Step 2 — Re-authorize the Box Drive

1. Select the Box drive in your drive list — don’t try to mount it yet.
2. Open the drive’s Edit panel from the drive list (the edit or settings icon next to the entry).
3. Find the account or authentication section and trigger re-authorization — this opens a Box login page in your default browser.
4. Sign in to Box and approve the access request again.
5. Save the drive configuration, then return to NetDrive.

If the Box login page never opens, check whether a corporate proxy or firewall is blocking your default browser, and confirm you can reach box.com directly before retrying.

Step 3 — Verify the Drive Mounts

Back in the drive list, click Mount. Give it 10–15 seconds on the first connection after re-authorizing — NetDrive needs a fresh directory listing from Box before the drive appears in Windows Explorer or Finder.

If it still fails right after re-authorization, check two more things:

• Admin approval pending. In a managed Box enterprise, ask your Box admin whether NetDrive is on the approved third-party app list. A user-level re-authorization cannot override an admin-level block.
• Stale credential cache on macOS. Open Keychain Access, search for entries tied to Box or your Bdrive account, and delete any that look duplicated or expired before repeating Step 2.

Keeping the Box Connection Stable

Once the drive is mounted and working, avoid revoking NetDrive from Box’s Apps list unless you mean to disconnect for good — that forces the full re-authorization flow again. If your organization manages Box centrally, ask IT to confirm NetDrive stays on the approved app list after any Box security policy update, since those updates are a common trigger for the errors above.

For the initial setup on each platform, see Mount Box on Windows with NetDrive or Mount Box on macOS with NetDrive. Teams sharing one Box drive across several people should also look at NetDrive Team Drive, which publishes a drive to members without distributing individual credentials.

— Casey, NetDrive