I/O Error is usually caused by Bad Blocks. You may have to Zero the WD passport before you can backup to it.
In Disk Utility, select he Physical Make & Model of the drive
. | Erase | pane ...
Click the ( Security Options ) button and [√] Zero Out data. This will take several hours. If it completes without error, your disk has 100 percent good blocks again.
Once the external HDD has passed the zeroing, if you want to have an exact copy of the internal HDD you need to clone it.
First go to the Partition tab and make sure it has a GUID Partition Table scheme. Repartition if necessary. Next, the volume needs to be in Mac OS Extended (Journaled) format. Re-erase if necessary, no need to re-zero a second time. Then go to the Restore tab, select the Mac's internal volume as the Source and the external drive as the Destination, and click Restore. Expect to wait several hours for the process to complete.
The 150GB on my boot volume take a tad under 2 hours to clone onto an external Hitachi drive via a FireWire 800 connection. USB will take longer. You may also want to look at CarbonCopyCloner to do this instead of Disk Utility. CCC will let you clone the all-important Recovery Partition as well as the main Macintosh HD volume. Saving the Recovery Partition is important if you don't want to have to re-download (and maybe even re-pay) Lion, as it contains a full installation image of the OS.
Your advice is very good, just one small inaccuracy:
Recovery HD does not actually contain a full image of Lion. (It is only about 650MB in size, and Lion is over 4GB.) It uses the Internet to get the parts it does not already have, so an Internet connection is required to restore. Recovery HD does contain Disk Utility and Password Reset, so it is very important.
There is a little program you can download from Apple that will add a Recovery HD onto another drive -- provided you have a working Recovery HD available to copy over:
True indeed, my mistake. Just checked the included image and it is accurately called "BaseSystem.dmg".
If you are game for Terminal highjinks, paste and run the following command in Terminal to mount the "invisible" Recovery Partition:
diskutil mount readOnly /dev/disk0s3
There, inside the com.apple.recovery.boot directory you will find BaseSystem.dmg. If you want to mount that too for inspection, paste and run the following command in Terminal after previous one:
hdiutil attach "/Volumes/Recovery HD/com.apple.recovery.boot/BaseSystem.dmg"
Both volumes will appear on the desktop.
Well, FYI: turns out that it was all due to a bad hard drive (wouldn't mount?). So the HD was replaced, and a valuable lesson was learned: Back-Up before you have a problem! Thanks for your input.
Murphy, that infamous foe, does have the habit of showing up at the most inopportune of moments.
ds store wrote:
Use a powered USB hub with port powered drives.
Or use FW drives while you still can. MUCH better performance and since the FW bus has 1.5A available for the peripheral, vs the USB's 0.5A, can handle a wider range of buspowered drives, especially the terabyte monsters.