Cannot open hard drive

Hard drives do fail and this may be the case here

Probably due to sleep mode. The computer will power off things such as USB ports. You can disable "Allow the computer to turn off this device to save power" under Power Management tab in Device Manager on each "USB Root Hub". Not sure if there is an equivalent on Mac

You got a loose wire or faulty cable. Best take it down to the shop and git em to fix it. Should cost ya around $10

Inside the LaCie D2 250GB (300770) external harddrive's case, is a 250GB IDE (PATA) harddrive that is 3.5 inches across in width.

A desktop computer sized harddrive. (May be a Western Digital WD25000JB)

The harddrive plugs into a small circuit board, (Bridge board), and the circuit board has a USB port on it.

Using this Western Digital Passport for an example,

http://www.xbitlabs.com/misc/picture/?src=/images/storage/wd-passport-250gb/p3.jpg&1=1

Scroll down to the second photo, and left-click on it. The case of the external harddrive is shown open.
Inside is a 2.5 inch laptop sized harddrive.
An aluminum tape strip covers the small circuit board, attached at the back of the harddrive.

The second photo down on this page, shows you the small interface circuit board, that the harddrive plugs into, with the aluminum tape removed.

http://www.xbitlabs.com/articles/storage/display/wd-passport-250gb_2.html

(Another design has wires coming from the small circuit board, to an interface the harddrive plugs into )

It is this small circuit board that goes bad in a LaCie. QUITE common.

Solution?

Simple.
1) Obtain a 3.5 inch IDE external enclosure
2) Remove the 3.5 IDE harddrive from the LaCie's case.
3) Install the harddrive out of the LaCie into the external 3.5 IDE enclosure.

An example of a 3.5 IDE (PATA) external enclosure,

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1733195&CatId=2779

For additional questions please post in a Comment.
Regards,
joecoolvette

The flickering light signals that the internal controller board has failed. Unfortunately this is terminal, the external case is dead. If you're really lucky the hard drive inside it still has enough life left in it to allow you , when connected directly to a desktop, to copy all your files from it.
After that just junk it and get a new one.

-Turn the drive off
-When pushing the power button to switch the drive ON, keep holding the power button until the blue LED of the power button starts to flicker and then release the button.
-Then, after 1 or 2 seconds the button's LED should flicker with another rhythm.
-Push the button again. After a few seconds, the LED will flicker again but with a third different rhythm. Release the button. -If the drive turns off then the power button was held in two long during the last step, please try again if the drive powers off.

The product should now be reset to its factory default settings.

In the logon window that opens, type:

User Name: admin
Password: admin

(This user name and password is the factory default; if you have already created a user, input your user name and password. This is the administration logon and you can change it for more security if you choose.) The NAS Administration page will open in your default browser.

The Lacie has four major components:

* the USB cable

* the power-adapter

* the disk-drive inside the enclosure

* the USB-to-disk-drive adapter inside the enclosure.

One of these components has failed.

Try a different USB cable.

Try connecting to a different USB port on your computer.

Try connecting to a USB port on a different computer.

Take a "multi-meter" and measure both the voltage and amperage output from the AC adapter, and compare with the specifications on the label on the adapter.

Open the enclosure, and remove the disk-drive, and then connect it as a "slave" disk-drive in a desktop computer, to see if it works at all.

Purchase a new, compatible, disk-drive, and install it in the enclosure, to "revive" your external storage device.

Get the part-number and serial-number from the label on your disk-drive, and access the manufacturer's web-site, and use "check warranty status", to see if they will replace the device, at minimal cost to you.

Sound very much like ypur disk is fried. Slim to zero chance of recovery.

The hard drive has it's own power supply. If you look on the back of the external hard drive, there is a power button there to turn it off. It doesn't shut off just cause you disconnect it from the PC or turn the PC off.