Fix 'The operation can’t be completed' Error on Mac External Drives

Quick answer for advanced users: Run diskutil verifyVolume /Volumes/[DriveName] and diskutil repairVolume in Terminal, or use Disk Utility First Aid. If that fails, force unmount with diskutil unmount force /Volumes/[DriveName].

What's going on here?

That dreaded 'The operation can’t be completed because an unexpected error occurred’ message usually pops up when you're copying files to or from an external drive, or trying to eject one. I've seen this on drives formatted in NTFS, exFAT, and even APFS. The underlying issue is almost always a file system glitch—the drive thinks it's still busy, or a directory entry got corrupted after an improper ejection. Last month, a client's Time Machine backup drive wouldn't eject after a power surge; this error showed up every time we tried to copy photos off it.

Apple's error handling is notoriously vague here. The error code (usually -36, -37, -50, or -8087) doesn't tell you much. But don't panic—it's rarely data loss. It's just macOS being overly cautious.

Step-by-step fixes (start here)

Unmount and remount the drive
Open Finder, right-click the drive on the desktop or in the sidebar, select Eject. Wait 10 seconds, plug it back in. If it won't eject, skip to step 3.
Run Disk Utility First Aid
Go to Applications > Utilities > Disk Utility, select the external drive (not the volume underneath—click the physical disk icon), then click First Aid → Run. Let it finish. This fixes 80% of cases.
Force eject from Terminal
Open Terminal, run diskutil list to find the drive's identifier (like disk2s1). Then: diskutil unmountDisk force /dev/disk2 (replace disk2 with yours). This forces the drive to detach.
Repair volume with Disk Utility (advanced)
If First Aid fails, boot into Recovery Mode (Intel: Cmd+R at startup; Apple Silicon: hold power button), open Disk Utility from the menu bar, and run First Aid again. This runs a deeper scan that bypasses corrupted system caches.

If the main fix doesn't work

Try using the `fsck` command line for older HFS+ drives

For drives formatted as Mac OS Extended (Journaled), you can do fsck_hfs -fy /dev/disk2s1 in Terminal (with the drive unmounted). This is what First Aid runs under the hood, but sometimes the verbose output helps spot the issue.

Check for Spotlight indexing conflicts

Spotlight can lock a drive while indexing. Disable it temporarily: System Settings > Siri & Spotlight > Spotlight Privacy, add the external drive, wait a minute, then remove it. This forces a reindex but clears any stuck locks.

Third-party NTFS drivers are a common culprit

If you're using Paragon NTFS or Tuxera, try unmounting the drive, quitting the driver app, and using Apple's built-in (read-only) NTFS support instead. I've seen this error on a Seagate drive formatted as NTFS after a macOS update broke the driver compatibility.

Prevention tip

Always eject drives through Finder — never just unplug them. That sounds basic, but I see this daily. Also, if you use exFAT drives for cross-platform work (Windows + Mac), run chkdsk /f on Windows every few months. exFAT has no journaling, so it's prone to corruption. On macOS, run Disk Utility First Aid monthly on drives you write to frequently.

Pro tip: If the error shows up when copying files, try copying one file at a time. If a single file fails, it's likely that specific file is corrupted, not the whole drive. Skip it and move on.