2 days was the longest it ever went without the error message so I returned it for a refund this morning. It worked just the same, the error message will pop up anywhere from within a couple of hours to a day or two. I returned the drive to Best Buy and exchanged it for another new identical drive. The error message came back up that evening. WD tech support advised me to erase the drive and format it for Mac, not sure why you would have to do that for a drive already formatted properly but whatever. The only way to get it to work again is either force eject the drive or turn the computer off and back on as eject and WD Utilities diagnostics do not work after the error message is received. The next day though an error message popped up that said Time Machine couldn't complete the backup because an error occurred. I purchased my first My Passport for Mac 2TB a couple of weeks ago, it was a very easy plug and play installation and it backed up my computer in a matter of minutes.
