Q: Can't move files - The operation can’t be completed because the item is in use.

Might get a clue if you run this command in Terminal

lsof -l +L -R -V | grep /

lsof means list open files.

If you want to see what's open on the external

lsof -l +L -R -V | grep /Volumes

Also, open Activity Monitor>Active Processes

this is a problem that's become a huge issue for a great many people since Apple's launch of Mavericks. I have huge problems trying to transfer files to a networked NAS drive. It would seemlessly for the past 3 years, but since Mavericks, I always get this stupid error. The above advice is completely useless. I've spent hours researching this with many workarounds touted, but none of which provide a solution.

Trying to transfer files now means that I have to do each file seperately, sometimes 10+ times to get it to actually complete copying. If you copy multiple files and one is "in use", the system then deletes all the others.

Apple.... good, until it's complete rubbish.

And it's a huge problem being completely ignored by Apple...guess they're all too busy writing crappy code for icloud so they can participate in "the fappening."

Two insanely frustrating nine hour days to transfer 500 small .psd files...great job Apple. To whom shall I send my bill for carpal tunnel syndrome?

I'm having the same problem. Every time I try to move a file to my WD Cloud, the transfer gets close to 100% then gives me the "can't complete, file in use error." I don't recall this happening in past versions of OS X.

Are you guys trying to drag and drop those files, or to copy and paste them. It makes a big difference, because in OS X, you can only move files from one location to another on the same volume.

Sure, you can drag and drop files onto a network drive, but the files remain on your Mac, they're just copied onto the network drive.

I've tried both, copy/paste and drag drop. I get the same results. It's from my HD to a NAS.

"the operation can't be completed because the item is in use."

This didn't used to happen.

Have you checked permissions for those files? When you select them and press Command-I (that's the letter "i"), then expand the Sharing and Permissions section, does it say you (the user) can read-write those files? If not, click on the lock under that section, enter your admin password, and grant yourself read-write rights, then close the info window and try to move / copy-paste them again.

Yes, I've got read/write permissions on the files. I also have read/write access on the folders on my NAS.

Can you move those files from one directory to another on your Mac?

Yes, no problems there.

When you try to move them in Terminal, does it work?

Open Terminal, then type "mv" (no quotes) or "cp" (ditto) after the prompt, then drag-drop the file you want to move (mv) or copy (cp) onto the Terminal window, then drag-drop the icon of the folder or drive* you want to copy or move the file to, then press Enter.

Just try with one file, at first. If you get a message saying the operation couldn't be completed, add "sudo" (no quotes) in front of "cp" or "mv", and enter your admin password when asked to (the letters and digits won't show), then press Enter again.

* For the whole drive, go to Volumes in the Finder. For a folder or directory in the NAS drive, navigate to it in the Finder, then drag-drop the folder onto Terminal.

I found a service running in Activity Monitor along the lines of

"DiskUnmountWatcher"

I forced quit that process and then dragged and dropped an MKV file from HDD to a NASZ share no problem.

Hope this helps others.

themarcolv

disabling "DiskUnmountWatcher" worked for me.  Thanks, themarcolv!

I was investigating this same problem on our iMac running OS 10.10. When I checked Activity Monitor for the DiskUnmountWatcher process, I noticed that with two users logged in simultaneously, there were two instances of most of the system processes, including that one. If I logged out of the other user account, and consequently only had one instance of the DiskUnmountWatcher process running, I was able to copy multiple files onto the network drive with no problem.

If I were to speculate, I'd probably guess that DiskUnmountWatcher is adding some metadata to new files when it detects them being added to a mounted drive. If there are two instances of the process running, they both try to modify the file's metadata simultaneously and generate errors.

TL;DR: If you encounter this problem, try logging out all users other than the one trying to move files.