Unable to copy files on iPod
Which kind of iPod is this? iPod Touch? iPod Classic...

Apple recommends the following steps to troubleshoot iPod issues. Exactly how these steps are performed will depend upon which iPod and OS you're using:


Reset the iPod
Retry connecting. Use a different USB port and cable.
Restart your computer. Make sure you have the latest software
updates installed
Reinstall the latest version of iTunes and the iPod software. Connect the iPod and select
"Check for Updates" in the iPod's source page.
Restore the iPod. This erases everything and takes it back to its factory state.


These are the same troubleshooting steps taken at Apple retail stores. They will fix the vast majority of iPod issues. If they don't, the device has likely experienced hardware failure of some kind. If it's still under warranty you can ask Apple to replace it.

For advice on the above steps specific to your device you can visit Apple's iPod troubleshooting site.