When I try to move mid to large size files or multiple files to the drive, I will often get a delayed write fail popup, no matter what the source of the copied file may be. I had heard that this could be due to a usb power issue when using multiple large external drives, but it also does it when files are coming from the internal C drive with all the others disconnected. After the popup, the drive vanishes from the My computer screen, but does not power off or make any reset/powerup sound. After a minute or two, it will pop up the normal 'what do you want to do' message as if it has been plugged in. So far it has not done this when moving files FROM the drive.
I have run several SMART testing utilities, all pass on quick as well as deep scans. The latest was WD Lifeguard tools, which took about 7 hours, no errors reported.
I am using XP SP3.
The drive is a SATA 500GB in a Cavalry USB cradle, one of 2. The other is working fine.
I believe the drive is a Samsung.