DRIVER_POWER_STATE_FAILURE 0x0000009f

Hi,

I only ever get this BSOD when I run a backup to a Toshiba 1TB external USB drive. The script is set to shut down the PC when it has finished backing up. Mostly that works fine, but, maybe 20% of the time, I come back to find this BSOD, which occurs at shutdown, not during the running of the script.

I know that this BSOD is usually due to an external USB device and that re-installing drivers should fix it. But what drivers do I need to install? It's just a P&P device, there were no drivers to install of course. Maybe the BIOS (chipset) drivers for my PC? Or is it a Power managemnt problem??

If I run the script, then remove the USB HDD (via the system tray icon) before shutting down, I don't get a BSOD. Also, the BSOD never used to happen, it's only the past few months that it has occurred.

Thanks.