Frequent I/O exceptions on USB drive

[Tommac]

Hi,

I hope I didn't miss a thread where this problem has already been discussed, but forum search didn't find anything appropriate...

I'm doing a full backup (Backup all files script) to a USB drive (Freecom Toughdrive 250GB). I created a self-expanding 128bit AES encrypted image on that drive and am trying to backup to it. This setup has worked on other occasions, but it's giving me trouble now for whatever reasons.

Here's what happens:

At different times during backup SD! stops with an error. The log looks something like this:

| 12:23:14 PM | Info | WARNING: Caught I/O exception(5): Input/output error
| 12:23:14 PM | Info | WARNING: Source: /Users/thomas/Library/Caches/DashboardClient/09/02/2288547999-2538855461.cache, lstat(): 0
| 12:23:14 PM | Info | WARNING: Target: /Volumes/Schniposa2/Users/thomas/Library/Caches/DashboardClient/09/02/2288547999-2538855461.cache, lstat(): -1
| 12:23:14 PM | Info | Attempting to copy file using copyfile().
| 12:23:14 PM | Info | Attempting to copy file using ditto.
| 12:23:14 PM | Error | ditto: /Volumes/Schniposa2/Users/thomas/Library/Caches/DashboardClient/09/02/2288547999-2538855461.cache: Input/output error

The error occurs with different files each time, so it's not the file that's causing the problem I guess. The strange thing is this: After this error the drive is "dead", meaning that if I reconnect it, I get a message saying the drive is not recognized. Disk Manager detects the drive but no partition whatsoever. After I initialize the drive again, it works again.

I've tried to backup directly without using an image, which worked fine. But I'd like to backup to an encrypted image because I take this drive with me when I'm not home, and I wouldn't want my data to be readable if I happened to lose the drive. Backing up to an image and moving that to the drive would be an option, but would take too much time.

Any ideas as to what might be causing this problem?

Thanks
Tom

EDIT: Forgot to mention: SD! 2.14 (v82) on Tiger (10.4.11) on an Intel iMac 24"