Replace/upgrade a hard drive in My Book Pro II, Premium II, or World II

So I have a My Book Pro II with a failed disk… about a month after the 3years warranty ended… doh!

Disk A: failed : WCANUxxxxxxx
Disk B: good   : WCANUxxxxxxx

Reason for using time on this…
Well, a RAID1 / RAID0 external casing is not cheap, so of course I need a way to fix the problem with a new drive or upgrade both drives.

I have found this info also:

I contacted support, what to do about it…

first answer from WD support:
I looked up individually each serial number you gave me. The corresponding models for this serial number are below.


These models are Caviar Blue’s, so they need caviar in the casing.
If you put in a caviar green or black, it will not function properly.
If you wish replace your old defective drives, then you need to purchase caviar blue’s with the same model.
Since your current casing ( the my book that you have ) has an older controller, a different drive will not be recognized.

I wrote this back:
"You cannot buy disks available 4 years ago!
I need to upgrade the disks in the external enclosure or else I can’t use it!

Not available -> WD Caviar Blue WD5000KS 500 GB
Not available -> WD Caviar Blue WD5000AAJS 500 GB
Not available -> WD Caviar Blue WD6400AAKS 640 GB
Not available -> WD Caviar Blue WD7500AAKS 750 GB
Available -> WD Caviar Blue WD10EALS 1 TB

Please advise what +1TB drives I can install in the external enclosure.
Also is there a firmware available so that I could use any of the following drive generations like WD Caviar Green?
If there is no new firmware to support bigger drives, please request that it will be developed."

NB: you can actually still buy the WD7500AAKS and the WD6400AAKS, but why not upgrade to 1TB. Also the controller itself will not have a limitation at 1TB if it can handle 500GB disks in a RAID0.

next answer from WD support:
It is not possible at all to put in that casing a different model.
No upgrades are possible as the controller of the casing and the model do not match.
So it is not possible to buy another disk other than the identical model

I wrote this back:
The My Book Pro Edition II was available in these capacities:
WD20000C033-001 WDG2TP20000 2.0 TB
WD15000C033-001 WDG2TP15000 1.5 TB
WD10000C033-001 WDG2TP10000 1.0 TB
WD6400C033-001  WDG2TP6400  640 GB
WD5000C033-001  WDG2TP5000  500 GB
The controller of the casing is the same in all of them, so I can put smaller or bigger disks in the there (upgrade/replace).

Additionally the WD Caviar Blue HDD are std. SATA and can be used in any modern computer.

I point to the replacement specification on WD, where it only says that you need to use WD disks, it does not specify WD Caviar Blue or other limitations.
Dismantile and replace the failed hard drive in the WD My Book Pro II Dual-drive System following the directions in Answer ID 1464: How to dismantle a My Book Pro Edition II, to replace a hard drive.
“Important: The user serviceable enclosure will only work with replacement hard drives from Western Digital. Inserting a non-Western Digital hard drive into the enclosure could cause damage or data loss.”

Please refer to an official statement or support case for future reference, so this information is available online for the public.

So please advise how these two following disks can be used:
WD Caviar Blue WD7500AAKS 750 GB
WD Caviar Blue WD10EALS 1 TB

next answer from WD support:
I have to inform you that non of the changes that you make will recreate the volume on the unit.
Only a identical drive will enable the rebuild of the raid and making it a functional unit.
The unit has a software raid and this is partly on the drives programmed.
So if you take out one drive you can rebuild it if you take both drives out the software raid is no longer on the drives so no recreation possible.
A upgrade possibility of both drives is not possible as of this software raid.
If you exchange just one drive and this in a other model this is up to you as we don’t support this.
Because in a raid you always use the identical drives to make sure that you have a working raid.
I would advice you to recreate the unit with a WD5000KS or a WD5000AAKS and nothing else to have a proper working unit.

I wrote this back:
To recreate the volume on the unit it is of course necessary to have an identical disk or bigger for a RAID setup. If the HDD is different from the original, then performance and stability might suffer. In any case it is completely understandable that this scenario, with two NOT identical disks is not supported by WD.
I can only guess that WD has put a limitation on the possible alternative disks, like from other manufacturers, but this would only make sense in the warranty period. For support, there will be need to change the disks to different models as time goes by.

Since the unit has software RAID and this is partly programmed on the drives, then it’s important to note the differences between rebuilding the RAID1 (RAID0 has no Fault Tolerance, so no rebuild possible) and making a completely new RAID1 or RAID0 from scratch.
Also possible in advanced RAID systems you can increase the size of a RAID setup by adding bigger disks, this is not an option in any WD my book, I’m sure.
In my case I want to make a new RAID1 setup. I have already emptied the good disk in the my book pro II. I am just waiting to buy the right disk to upgrade the enclosure with, in case there are som built in limitations or problems.
So what I’m asking for is the supported drives in the WD my book Pro II.

my best guess till now is:
WD Caviar Blue WD5000KS 500 GB
WD Caviar Blue WD5000AAJS 500 GB
WD Caviar Blue WD6400AAKS 640 GB
WD Caviar Blue WD7500AAKS 750 GB
WD Caviar Blue WD10EALS 1 TB

Before there was mentioned that only the WD Caviar Blue line is supported. From what I can tell they are not developed/produced anymore, so the WD my book Pro II should also support the WD Caviar Green as they are used in the newer generation WD My Book systems.
I have heard that some 2TB drives could give issues (Advanced Format, 4K Sector), but a 1½ TB drive should be a good option.

I understand that WD needs to sell new hardware, but an RAID 1 og RAID0 external casing is not cheap, so of course I need a way to fix the problem with a new drive or change both drives. In my case change both drives.

NB: Advanced Format: The 4K Sector

next answer from WD support:
As informed only the WD5000KS and the WD5000AAKS as we don’t have any other testing values.
A Upgrade as you want is not possible.

I wrote this back:

As a customer I have bought an external enclosure with 2 preinstalled HDD’s that are user replaceable. WD needs to address the issue of replacing the user replace disks with current and future available disks.

If there are issue surrounding new technology such as Advanced Format, 4K Sector. WD also needs to address this with new firmware for the My Book.

Imagine selling a PC, laptop, etc. where you only can use HDD’s from the org. manufacturer that are several years old.

Many my book systems such as mine are still under warranty.

Please send this information and request on to a more qualified technician.

I will soon try a setup with different disks and see what happens… just need to find 2 disks that can be used …


I have a Pro II with a pair of 500GB WD5000AAKS myself. Coincidently also out of warranty since January :smiley:

Mine is working fine at the moment, but I can’t say I’d be happy at the notion of throwing out a perfectly good external case and PSU, and if I had to throw it in landfill for no reason other than WD abandoning it, I wouldn’t exactly be rushing out to buy another one from them.

Given the original cost of these things, it is disappointing (although sadly not surprising), that WD would be happy to render your external drive obsolete the moment the warranty is gone.

I’ll be very interested to see how this pans out for you, let us know how it goes.

hey dude ! im very glad to know that there are people testing the device as pushing it to its limits !

 i have a question about to upgrade a raid one feature ! supose that i have a raid one with 1tb size.

i wanna to upgrade it to as an example for a raid 1 with 1.5 tb.

i would take one driver off the raid 1 (break the mirror) then i would comeup with 2 1b  drives.

then i would atach a new blank 1.4 tb disk and pass all the info from the old one for it.

after this is done, i wold remove the other one and atach the second disk also with 1.5 tb size.

then i would recereate raid 1 mirroring with the boths disks.

is this capable on wd ? im used to do this od DL 380 HP servers, but not on these NAS devices.

on a raid controler  you just break the mirror,  revealing 2 separate drives.

if WD does this also, i know how to proceed.

has anyone of you done this on WD, to extend a mirrored raid  drive ?


Hi guys,

Some info which may be of use to you. I have a MyBook Pro 500GB model with a failed HDD (clicks of death etc). I bought the drive whilst living in the UK but as I now live in Switzerland, WD have been unable to replace my drive under warranty (go figure). I refrained from throwing the unit in the bin as I was never sure whether the controller was still OK.

Well, my LaCie Little Disk (320 GB 2.5" SATA USB 2.0) drive failed with a dead controller whilst on vacation recently so today I did a little Dr.Frankenstein style work.

I opened up both the LaCie and MyBook enclosures and connected the little 320GB drive from the LaCie to the controller in the MyBook. Powered up and it’s working just great with absolutely no fudging whatsoever. Plug-and-Play.

Now, the interesting point is that the drive from the LaCie is a Hitachi, so the information received from WD about their controllers only working with WD drives could *potentially* be incorrect.

As I said, mine is the regular MyBook Pro (ie: single disk enclosure) so I cannot guarantee the same for the Pro II and other multi-drive enclosures, but it might provide food for thought.

Sadly, I do not have a large capacity 3.5" SATA lying around to test with and I am not prepared to shell out on a drive that may not work with the WD controller so here endeth today’s lesson.

Go forth and experiment.



I would be very interested to know if you managed to replace the drives in the same WD case. i’m having a similar issue, I want to replace both drives in the enclosure…I’m just not sure what drives will work.

It would be nice to upgrade these drives even to  500GB Caviar Green drives. I have the 1TB dual dive MyBook Pro in Raid with 2xWD5000KS 500GB drives which is working. It is ++ warm  unit which is noisy with the fan. I also have a MyBook 500 FIrewire/USB with single WD5000KS 500 GB drive, which was not working (20GB transfer over FW400 took 5 hours!) and so I replaced with 1 TB Caviar Green. Same transfer was 1o minutes, and the drive is quiet and cool.

So while these units are a few years old, the FW/USB controller in an enclosure is worth some $$ and  I agree WD should have some option or fix to replace with at least current Green drives. I bet the fan wouldn’t kidk in and it would be much cooler running.

So I would love to hear if anyone was able to replace drives with other than original OEM 500GB drives.


Wondered if you had any further experiments or thoughts about this. I would love to replace the old drives in this enclosure.