"disappearing drive"

[falther]

I have a 2,5" hdd which will be recognized when starting the computer.
Very shortly after the system is ready a small window appears and an
error message explains that a device was (try to explain to english):
"Unexpected / not permitted removal of a device" - meant is the hdd.

After this, certainly its not possible to access the drive.

I made a complete image with the Ninja from YEC - took about 3,5 hours.
Tested yesterday with Data Compass from Savlationdata - which would have
taken about 13 hours (most probably due to the USB bottle neck).

My question to the pros:
What is causing such an error?
How can Ninja or CD bypass the confict? A matter of (no) BIOS?

[dick]

Hi, was it in windows or linux you get the error?

Maybe its due to the drive failure to respond within a certain time period...'time out'

What happens if you attempt to access the drive in a Dos environment?

[falther]

Sorry, I was not clear enough:

Windows 2000
the drive was detected during boot up
the drive existed in Windows for 20 to 50 seconds - and then the error occured
I did not try with DOS yet.

the image with Ninja was complete and no data was missing - the image works perfectly.

My question was only to understand what happens respectively what can cause such
an error.

Thank you