You're in the middle of copying a folder of photos to an external drive, and just as the progress bar hits 80%, macOS stops dead and pops “The operation couldn’t be completed.” No error code, no explanation. Infuriating, right? I’ve been there, and I’ve spent years troubleshooting this exact message on everything from ancient MacBook Pros to the latest Apple Silicon.
The truth is, this generic message is macOS’s way of saying “something went wrong, but I’m not going to tell you what.” The fix depends on what’s actually failing, but in most cases, it’s one of three things:
- A Finder preference file got corrupted.
- The disk (internal or external) has a filesystem issue.
- A permissions conflict is blocking the operation.
Let’s walk through the fixes, in the order I’d try them. I’ll skip the junk like “restart your Mac” – though if you haven’t tried that, go ahead, it’s a 30-second test.
Fix 1: Reset Finder’s Preferences (Fast, No Data Loss)
This is the first thing I try when the error appears out of nowhere, especially after a macOS update or if you’ve been messing with Finder view options. A corrupted com.apple.finder.plist file can cause all sorts of ghostly errors, including this one.
- Quit Finder entirely: Right-click the Finder icon in the Dock, hold Option, and click Relaunch.
- Open Terminal (find it in Applications > Utilities).
- Type this command and hit Enter:
rm ~/Library/Preferences/com.apple.finder.plistThis deletes the preferences file. Don’t worry – it won’t delete your bookmarks or files. It just resets Finder’s view settings, like whether you show icons or list view.
- Relaunch Finder again (right-click icon, Option, Relaunch).
- Try the operation that failed again.
If the error persists, or if you’re getting a specific error code like -36, -43, or -50, jump to the next fix.
Fix 2: Repair the Disk with First Aid
Error codes are the best clue you’ll get. Here’s what they mean:
| Error Code | Meaning |
|---|---|
| -36 | I/O error – usually a bad sector or a file that’s corrupted. |
| -43 | File not found or a permissions problem. |
| -50 | Parameter error – often happens when file names contain weird characters. |
All three scream “disk problem.” The built-in First Aid tool can fix many of these issues, but you need to run it from Recovery Mode because the system volume is locked during normal startup.
- Shut down your Mac.
- Turn it on and immediately press and hold Command + R until you see the Apple logo or the startup options window.
- In the utility window, choose Disk Utility, then click Continue.
- Select your startup disk (usually named “Macintosh HD”) from the sidebar.
- Click First Aid, then Run. This can take a while – let it finish.
- Also run First Aid on any external drives that were involved in the error.
After it’s done, restart normally and try again. If First Aid reports an error it can’t fix, you might need a third-party tool like DriveDx, but that’s a last resort.
Fix 3: Check Permissions on the Target Folder
If the error happens when copying to a specific folder (like a shared folder or an external drive you didn’t format yourself), permissions are the usual suspect. macOS is picky about ownership.
- Right-click the folder you’re trying to write to, and select Get Info.
- At the bottom, expand Sharing & Permissions.
- Make sure your username has Read & Write access. If it says “Read Only,” click the padlock icon, enter your password, and change it.
- Also, check the gear icon and click Apply to enclosed items – this fixes subfolders too.
For external drives, the whole drive should be set to “Ignore ownership on this volume” if you’re the only user. I’ve saved countless drives this way.
Still Failing? Here’s What to Check Next
If none of those worked, don’t throw the Mac out the window yet. Try these:
- Check the file name. Error -50 often happens when a file has a slash (
/) or a colon (:) in its name. Rename the file, keeping it simple with letters and numbers. - Test a different USB port or cable. Flaky hardware causes I/O errors that mimic this message. I’ve seen a cheap USB-C cable create chaos.
- Reset NVRAM. On Intel Macs, shut down, then power on and hold Option + Command + P + R for 20 seconds. On Apple Silicon, it happens automatically when you restart – just restart twice in a row.
- Try copying via Terminal. Sometimes the Finder chokes on a file, but
cpwon’t. Open Terminal and run:
cp -R /path/to/source /path/to/destinationIf that works, the problem is Finder-specific, and resetting its preferences (Fix 1) usually nails it.
The “operation couldn’t be completed” message is vague, but the fixes aren’t. Work through them in order, and you’ll solve it 9 times out of 10. If you’re still stuck, post the exact wording and any error code in the comments – I’ll help you dig deeper.