You're copying a folder full of photos from your Mac to an external drive, or maybe you're moving a project folder to a USB stick. Halfway through, Finder stops and throws up a dialog that says: "The operation couldn’t be completed. (OSStatus error -36.)" It's frustrating because the first few files copied fine, then it just quits.
This error is old — it's been around since the classic Mac OS days. It usually means the file system on the destination or source drive can't handle something about the files you're copying, or there's a corrupt file somewhere in the mix. The most common trigger I see is copying to or from a drive formatted as FAT32 or exFAT, especially when one of the files has an unusual metadata attribute or a filename that trips up the older file system.
What causes OSStatus -36?
At its core, OSStatus -36 is a generic I/O error. The OS tried to read or write a file and the file system returned a bad status. It's not a hardware failure — it's usually a logic problem. For example, a file might have a resource fork (those are leftover from old Mac apps) that doesn't translate to FAT32. Or you've got a file that's actually a symlink, and the destination drive doesn't support them.
The real fix depends on what you're doing. If you're copying to an external drive, the quickest fix is often to reformat that drive to a Mac-friendly format like APFS or Mac OS Extended (Journaled). If you can't reformat (because you need to share with Windows), then you need to find the problem file and skip it or change its metadata.
But don't jump straight to reformatting — you'll erase everything on that drive. Try the simpler steps first.
Fix 1: Copy in smaller chunks
Sometimes the error is just a single bad file. Instead of copying the whole folder, copy subfolders one at a time. When you find the folder that fails, drill down until you isolate the file that triggers the error. Then you can decide what to do with it.
Fix 2: Use the Terminal to copy (bypasses Finder quirks)
Finder hides a lot of file system details. The Terminal doesn't. Using ditto or rsync can work around the issue because they handle metadata differently.
- Open Terminal (found in /Applications/Utilities/).
- Type this command, but replace the paths with your actual source and destination:
ditto "/Volumes/SourceFolder" "/Volumes/DestinationFolder"Press Return. You won't see a progress bar, but it will copy the files. If it errors, it'll tell you which file caused the problem. Note the file name — that's your culprit.
If ditto doesn't work, try rsync:
rsync -av --progress "/Volumes/SourceFolder" "/Volumes/DestinationFolder"After either command finishes, check your destination folder—you should see all the files there.
Fix 3: Clear the file's extended attributes
If you isolated a specific file that fails, it might have extended attributes (like quarantine flags or custom icons) that the destination drive doesn't like. Clearing them usually does the trick.
- In Terminal, navigate to the folder with the problem file:
cd "/path/to/that/folder"xattr -l "filename.ext"You'll see a list of attribute names. Don't panic—if you see com.apple.quarantine or com.apple.FinderInfo, those are common culprits.
- Clear them all:
xattr -c "filename.ext"Now try copying that file again. It should go through.
Fix 4: Reformat the external drive (if it's not your only copy)
If you're copying to a drive that's formatted as FAT32 or exFAT, and you don't need Windows compatibility, reformatting to a Mac format will solve this permanently. This erases the drive, so back up anything on it first.
- Open Disk Utility (found in /Applications/Utilities/).
- Select your external drive in the sidebar—not the volume underneath it, the whole drive.
- Click Erase in the toolbar.
- Name it whatever you like.
- For format, choose APFS if you're on macOS 10.13 or later, or Mac OS Extended (Journaled) for older systems. If you're using a mechanical hard drive and it's not an SSD, Mac OS Extended is actually snappier.
- Click Erase and wait for it to finish. You'll see a confirmation when it's done.
After that, reattach the drive and try your copy again. It'll work.
What to check if it still fails
If you've tried all the above and you're still getting OSStatus -36, then you're likely dealing with a failing drive. Run First Aid in Disk Utility on both the source and destination drives. That checks for directory corruption.
Also, check if the source drive is nearly full. A full drive can throw weird I/O errors. Clear up some space and retry.
One more thing: if you're copying over a network (like to a NAS), that changes the game. Network file systems have their own quirks, and error -36 might actually be a connection timeout. Try copying to a local folder first to rule that out.
When all else fails, compress the problem folder into a ZIP (right-click, then Compress) and copy that ZIP. It'll likely go through, because the ZIP format sidesteps the metadata issue. Unzip it on the destination.
You won't see this error every day, but when you do, it's rarely a hardware disaster. Walk through these steps in order and you'll be moving files again in no time.