setup: One comp running win server 2003 with an external USB drive.

My laptop running vista.

The aim is to access files on that external USB drive and open them on my laptop. I set it all up and it worked (assigned drive letters etc...).

switch the USB drive off and on again, still works fine.

Heureka? NO!

trying it again this evening, it says cyclic redundancy check error. The shared folders on the server's internal HDD are working fine.

any advise out there?

reboot server.

check your usb disk, cyclic redundancy checks might point to faulty disk, usually this occurs with CD/DVD media though.

Run chkdisk/r on the server, also check whether you are also getting CRC erorrs when the disk is connected to other computers, also consider that the CRC check can be from the source rather then the target.

You may want try "spinrite". small program that will make a boot disk and diagnose any hard drive, yes even external usb. It has save many of "dead" HDs 4 me.

If you cannot find it, PM me and I'll attach an "evaluation copy" via email. Good Luck