macOS “The operation couldn’t be completed” Fix

You’re trying to copy a folder to an external drive, delete a stubborn file, or eject a volume—and instead of doing what you asked, macOS throws up a dialog that says “The operation couldn’t be completed.” Sometimes there’s a code attached, like -36, -8058, or 100093. Sometimes there’s nothing but a gray OK button. This error doesn’t care if you’re on Sequoia or Catalina; it’s been haunting Macs for over a decade.

What’s actually happening here is that macOS is failing a filesystem operation and can’t give you a specific reason. The Finder, or the app you’re using, is catching a generic NSError from the kernel or the file system driver and passing it straight to you. It’s a catch-all for “something went wrong and I don’t know or won’t tell you what.”

Why does this happen?

The root cause is almost always one of these three things, in order of likelihood:

1. Permissions are broken — the file or folder you’re touching has ACLs or POSIX permissions that contradict what you’re trying to do, and the system won’t just let you override them silently.
2. APFS or HFS+ metadata is corrupted — a directory entry or a symlink is pointing nowhere, and the filesystem is bailing out.
3. A Finder or related process is stuck — the Finder itself has a stale cache or a hung extension, and restarting it clears the cobwebs.

The fix below handles all three cases. Skip the parts that don’t apply.

The fix, step by step

Start with the least destructive option and work your way down. Don’t jump straight to the terminal if you’re not comfortable—but honestly, the terminal is the most reliable path.

1. Restart the Finder

The Finder is just an app, like any other. If its internal state is messed up, restarting it often clears the error. Open Terminal (you’ll use this a lot) and type:

killall Finder

That’s it. The Dock will blink, the Finder restarts, and you can try the operation again. This fixes maybe 20% of cases, usually the ones where you were ejecting a volume or copying within the Finder.

2. Check permissions on the target file or folder

If the Finder restart didn’t help, the next suspect is permissions. Right-click the file or folder that’s failing, select Get Info, and look at the Sharing & Permissions section at the bottom. If your username isn’t in the list with Read & Write, that’s your problem.

To fix it from the terminal, run:

chmod -R u+rw /path/to/file

Replace /path/to/file with the actual path. You can drag the file from the Finder into the Terminal window to get the path automatically. This recursively adds read and write for the owner. If the error was permissions-related, this clears it.

3. Reset the file’s ACLs

POSIX permissions aren’t the whole story. macOS also uses ACLs (Access Control Lists) that can block operations even when the POSIX bits look fine. To strip them off:

sudo chmod -R -N /path/to/file

You’ll need your admin password. The -N flag removes all ACLs. This is a sledgehammer—use it only if you know the file isn’t shared or managed by another system.

4. Run First Aid on the disk

If files still refuse to cooperate, the filesystem itself might have metadata damage. Open Disk Utility, select the disk (not the volume—the whole disk), and click First Aid. Let it run. It can take a while on a large drive, but it’s non-destructive.

You can also do this from the terminal:

diskutil verifyVolume /

That checks the boot volume. If it reports issues, run:

diskutil repairVolume /

If the disk is the boot volume, you might need to boot into Recovery mode to repair it—First Aid from Disk Utility will often tell you if that’s necessary.

5. Restart in Safe Mode

Safe Mode (hold Shift while booting) does three things: it checks your directory, disables third-party kernel extensions, and clears some caches. If the error disappears in Safe Mode, you know a third-party extension or login item is the culprit. Log back into normal mode and start removing recent installs.

What if it still fails?

If you’ve done all of the above and the error persists, you’re likely dealing with a file that’s genuinely corrupted or on a dying drive. Copy the data off with rsync (it’s more forgiving than the Finder):

rsync -avh /source/ /destination/

If rsync throws errors, that’s a strong signal the drive is failing. Back up what you can and replace it.

Also check if the issue is specific to one app. If it happens only in Photos or Mail, that app’s library might be the problem, not the filesystem. In that case, running a database rebuild or resetting the app’s preferences is more likely to help.

One last thing: if you’re on an external drive formatted as ExFAT, the error is often a driver bug. Copy the files to your Mac’s internal disk, reformat the external drive to APFS or HFS+, and copy back. It’s not elegant, but it works.