Why does Mac OS X sometimes complain that a copy failed because a file is in use?

Solution 1:

The problem is Quick Look. As soon as you open a folder in the Finder it tries to create previews.

I'm running 10.5.7 and still get this problem all the time transferring video files from external drives. Only solution seems to be to open the folder, wait for the preview icons to appear and then try to copy the files.

A possible solution is to disable "Show icon preview" in the Finder view options. That only occurred to me, so I haven't tested it though.

Solution 2:

Show icon preview is the problem! Put it on list view and there are no problems. It's a bug!

Solution 3:

The only way I can do it is to use the Terminal Application and either use mv to move then or cp to copy the required files to the network or external drive.

Solution 4:

The utility What's Keeping Me? for OSX may help you find out what's keeping it from working. Basically, it lets you find out what process has a file open.

Have you ever have the problem where you can’t empty the Trash or eject a disk because something is preventing you? Usually the reason is because some application has a file open, and thus you can’t get rid of the disk or trash the file. That’s why we made What’s Keeping Me! What’s Keeping Me will identify the application that is holding the item open. You can then use What's Keeping Me to quit the problem application (or kill it if needed) so you can perform your task. What’s Keeping Me includes an Automator workflow so you can perform searches directly from the Finder too!