Error "One or more items can't be copied" when backing up to USB hard drive

Question

I just bought a 160 GB USB2 external hard drive for use with my PowerBook. It seems to work just fine for the most part, as long as I'm working with one or two files at a time.
One motivation for the purchase, however, was backups. The first thing I wanted to back up was my home folder. Feeling like the savvy Macintosh user I logged out of my account and logged back in as the root user, and dragged my Home folder to the external HD. After watching it "prepare" to copy for a few minutes it started. Then stopped almost immediately with the warning "One or more items can't be copied. Do you want to skip them and copy the remaining items?"
Seeing as how I didn't know which items stopped the copy, I didn't want to skip them. A backup with holes is not a backup.
Thinking I'd bitten off too much, I started moving one folder at a time. Music, Documents, etc. But each folder ran into the same error.
I've tried dragging folders over from inside my own account, thinking that perhaps root (yes, I know this sounds absurd) didn't have privlidges. No go, I still run into the error, even when copying files I know aren't in use (my Music folder, for example, when iTunes isn't running).
I have way too much in that folder to drag individual files for backup. Can someone please tell me what I am doing wrong? I have another 10 days to return this HD, and if I don't get this working soon I see no reason to keep it.

Answer 1

This problem can occur for several reasons. One, is that you aren't logged in as the root user. Keep in mind that your admin account does not convey root user privileges. Second, when trying to copy system files that are in use you will get that error. Third, you cannot make a proper clone of your system using drag and drop. Instead do the following:
First, prep the external drive properly:
1. Open Disk Utility in the Utilities folder of your Applications folder.
2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Click on the Partition tab in the DU main window.
3. Set the number of partitions from the dropdown menu (use 1 partition unless you wish to make more.) Set the format type to Mac OS Extended (Journaled, if supported.) Click on the Partition button and wait until the volume(s) mount on the Desktop.
4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.
5. Set the format type to Mac OS Extended (Journaled, if supported.) Click on the Options button, check the button for Zero Data and click on OK to return to the Erase window.
6. Click on the Erase button. The format process will take 30 minutes to an hour or more depending upon the drive size.
Next, create the clone:
1. Open Disk Utility from the Utilities folder.
2. Select the startup volume from the left side list.
3. Click on the Restore tab in the DU main window.
4. Drag the startup volume to the Source entry field.
5. Select the backup volume from the leftside list and drag it to the Destination entry field.
6. Double-check you got it right, then click on the Restore button.
Keep in mind that according to Apple you cannot start up OS X from a USB drive. If one of your goals was to be able to boot from the external drive, then you should have purchased a Firewire drive.