My lacie mobile disk 500gb USB 2.0 will not show in my laptop or in any computer

well we all have had that problem I have sent back items that were bad when I toke them out of the box before

just run disk management and enable entire volumne on the Lacie

Which "disk utilities" did you use?
Ones that check the "file-system-integrity" (that every file on the disk is listed in the table-of-contents, and that no 2 files point to the same block on the disk)?
Ones that write data to every block on the disk, and read the data back, to confirm that the disk can _correctly_ store data ?

What computer? Desktop? Laptop?

How much voltage/amperage does each USB port supply to the connected USB device?

Are you connecting the devices to a USB hub, or directly to your computer?

Do the external disk-drives each have their own power-supply?

Right click "My Computer" and select Manage. In the window, select Disk Management on the left column. If the drive is not listed on the right column, then the BIOS has not detected the harddrive - it might have a harddrive password lock. You will need to go into the BIOS and unlock it with the password.

1. the usb connector in the PC may have a broken board contact needs soldering or replacement.
2. there may be a broken USB cord to the external usb drive
3. the electronic controller in the USB case may not be working.
4. A new case may be needed with a new controller.

If it still is under warranty, then exercise the warranty, and get it repaired/replaced.

If it's out-of-warranty, then disassemble the case, and disconnect the disk-drive from the USB-to-disk-drive adapter.

Connect the disk-drive as a "slave" disk-drive in a desktop computer, and see if the disk-drive still works.

If it's dead, it's dead, unless you pay mega-dollars to a professional "Data Recovery Service" to rescue your files.

If it is dead, then buy another disk-drive that is compatible with that USB-to-disk-drive adapter, and reassemble the unit, and you'll have a brand-new external drive that you can use.

Disassemble the case, and remove the disk-drive.
Attach it as a "slave" disk-drive in some desktop computer, and see if the desktop computer can "detect" the disk-drive, and if the files on the disk-drive are still accessible.

try restarting you rcomputer

did you check the jumper settings.