Lacie big 5 led on red - LaCie 5TB 5big Network 2 )

You didn't provide details on what mode you were running or if this worked before and this is a sudden event. The manual doesn't appear to cover this situation of one blinking red light: https://www.lacie.com/download/manual/UM_2big_Quadra_EC_EN.pdf
but I found a YouTube video that may be helpful to you:
http://www.youtube.com/watch?v=V8KbtZYytC0

Hello, I had similar problem with 2Big Network2 which was freezing the same way. I know the question is old but maybe someone will find this answer useful.

I solved the problem by updating the firmware. It may seem trivial but it took some time to figure out how to do it right.

My firmware was 1.3.7 and I was unable to easily get SSH access.

To upgrade the disk you have to
1. get it recognizable by Lacie Network Assistant. If you have a fixed IP it may not see the disk. To switch your device to DHCP assigned IP you have to reset it to factory settings (without losing data). Procedure from LaCie site works (http://manuals.lacie.com/en/manuals/d2-2big-5big-network2/reset)

1. Make sure the product is turned OFF.
2. Press and hold down the front button. Without releasing the front button, turn the product on by pressing the power switch on the rear of the product.
3. Keep the front button pressed until the front LED becomes solid red, then release it. (The LED should become solid red about 10 seconds after you turn on the product.)
4. The front LED will blink blue. When it becomes static blue, press the front button once within 5 seconds to confirm reset.
5. If any of the steps are omitted, the product will boot normally without resetting.

2. you need the LaCie Network Assistant which you can download from here http://www.lacie.com/support/drivers/driver.htm?id=10138
I used 1.5.15 version for windows
3. Once you have the LNA installed it should recognize the disk. However if it doesn't start and says you are missing bonjour service just go to the installation directory and install bonjour.msi
4. At this point you should be able to start LNA which finds your drive. Now you need firmware (capsule file). You can't just load the newest firmware out there. Given fw version can be applied only to certain previous revisions. To check which version you need you have to check your current release. To get your current release open LNA and go to Configuration tab. The current system version is displayed in the bottom-left corner.
I updated mine to next release (from 1.3.7 to 2.0.5).
5. Now you should now to which release you should update. The question is where to get the firmware from if the LaCie support page (http://www.lacie.com/fi/support/drivers/driver.htm?id=10201) does not contain the one you need ? You can use and ftp service (it's not obvious).
Go to ftp://2bignetwork2-update.lacie.com/ (just put this address in files explorer address field) and login with 2bignetwork2 user and 2bignetwork2 password. Then browse for firmware.
6. now assuming you have successfully downloaded the firmware open LNA go to configuration tab and click "Update your NAS.." button. Authenticate with admin user and admin password then browse for the capsule file and begin updating
7. drive will need couple minutes to finish (blinking blue-red) then it will restart and when the light turns solid blue you should be able to get access to the web administration interface.

As other suggested - if you don't want to risk losing data get disk(s) (if in RAID0) and use some linux box or VM to backup data.

LED Indicators - LaCie 2big Network
The LED indicators above the drive bays and the front LED indicate drive status and activity.
During Startup

• Front LED – blinks red/blue until both disks are powered on, then turns solid blue.
• Rear LEDs – blinks red/blue until corresponding disk is powered on, then turns solid blue.

NOTE: If the device is not able to initiate the boot process following disk startup, the front is solid red.
During Bootup

• Front LED – solid blue
• Rear LEDs – solid blue

NOTE: If a disk is failing, both the disk’s corresponding rear LED and the front LED will be solid red.
During RAID Synchronization

• Front LED – solid red
• Rear LEDs – The LED corresponding to the original disk will be blinking blue and the one being synchronized is blinking red
• Once both disks are synchronized, their corresponding rear LED and the front LED will be solid blue.

If the drive front LED alternates between Red and Blue, whilst the rear LEDs are normal, then it is a tempertaure warning. Ensure that there is plenty of space around the drive and at the rear.

Hmmm, reseting worked on mine. Identical symptoms except light stayed blue, not red. Unable to power down.
Before trying to get the drive working I got the data off using the procedure in the second post of this thread:

http://www.linuxforums.org/forum/peripherals-hardware/126831-reseting-lacie-2big-network.html

You need a linux system running. Maybe a live cd will do. I installed on an old IDE drive I had.

I then rest the decive using this procedure from Lacie and my drive is working again. Worthless though, because I can't trust it.

The procedure below will reset the 2Big Network to factory settings:
IMPORTANT NOTE: Following the procedure below can ERASE ALL DATA on the drive. Prior to following these directions, verify important data is stored securely on a different storage device.
Switch the drive OFF. Once it has shut down, ensure the power switch remains in the OFF position.
If the drive is in the SAFE mode, move the RAID switch to the BIG mode.
PRESS AND HOLD the button on the front. MOVE the power switch to the ON position. The light on the front of the drive will start blinking.
Once the light stops blinking, RELEASE the front button.
When released, it will begin BLINKING AGAIN. When it stops, PRESS AND HOLD the front button. The light will begin to blink again.
When the light stops blinking, RELEASE the button. The drive is now resetting itself. Switch the RAID selector back to SAFE if desired.
To restore data if it was lost during the process, recreate the shares and users on the unit prior to the reset. Any firmware updates applied will need to be applied again.

256

500Gb Lacie D2 Quadra with the same problem of flashing led and not mounting on the desktop (Mac G4 Mirror), traced to the power supply (57w) going down on power, both 12v and 5v supplies are available but the main power to run the drive drops to below an adequate output, hence the clicking and whirring evident from the drive with simultaneous flashing led.

Testing with another Lacie power supply (250Gb D2) this time a 34w unit got the drive up and running, however, and this is the reason for this post, this lower power PSU failed a week later whilst waiting for a warranty replacement from Lacie (5 weeks and still waiting for the new PSU from them. they have no stock)

Message for all Lacie D2 users, check the power supplies first, test with another Lacie PSU, do not run the drive on a lower rating (34w) PSU it will fry it and leave you with another failed power supply.

If you are in a tight spot use the temporary power supply to move your data to another drive and get the correct 57w power supply before running the drive again.

Don't do as I did assume any Lacie power supply will run any Lacie hard drive, they won't, fortunately I had a second back up, but am 2 drives down and no new PSU's available to buy anywhere.

Try and purchase another spare 57w power supply, something all D2 users should do for long term security, as these do not seem to be very reliable and getting warranty support from Lacie on these is currently impossible.

The lack of 57w power supplies from Lacie and its distributors across the world is surely a warning to be noted!!!!!!

Buyers beware!

Solved! After 17 hours of blinking, the status of the 3 leds is now to fixed blue. You just have to be patient...
Note that I had only put 1GB of data on the drive. I expect that the resynchronization time is not proportionnal to the amount of data on the disk!

well the best thing i figured out to do was to purchase a new case. i think the case burned up. i pulled the hard drive out and hooked it up to another drive so to see if it would work. the drive works just fine in the other device, so i ordered another case.