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Formatting hangs on "Unmounting drive"

Before formatting, DCP Transfer asks macOS to release the drive. If another app is still using it, or the app's helper tool is out of date, it waits on "Unmounting drive to check parameters..." and never moves on.

Try these first

  1. Close anything using the drive. Quit Disk Utility, Finder windows open on the drive, and backup or sync apps such as Time Machine. If you used Disk Utility on the drive, log out and back in (or restart) before formatting.
  2. Connect the drive directly. Plug it straight into the Mac, not through a hub, dock or adapter chain. Some drive docks don't pass the commands DCP Transfer needs.
  3. Format on its own. Use File > Format Drive first. Once that finishes, run the transfer with Format unchecked, then validate. Splitting the job into three steps makes it clear which one is failing.

Reset the helper tool

DCP Transfer installs a small helper that does the actual formatting. If an old copy is left behind from a previous version, the two can conflict.

  1. Quit DCP Transfer.
  2. In Finder, choose Go > Go to Folder (Command-Shift-G) and enter /Library/PrivilegedHelperTools/
  3. Delete any files that start with com.cinematiq.DCP-Transfer.Helper. You'll be asked for your password.
  4. Open DCP Transfer. If it shows an update error, dismiss it.
  5. Let the app reinstall the helper tool when it asks, then try the format again.

Drive tips

  • Drives larger than 2TB may not format correctly. Use a drive of 2TB or less if you can.
  • If one drive keeps failing and another works, the drive or its enclosure is the likely cause.

If it still hangs, see Contacting DCP Transfer support and include the log files.

Formatting hangs on "Unmounting drive" — DCP Transfer Help — Cinematiq | Cinematiq