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"MediaKit reports block size error" when formatting drive

I got a new 2TB hard drive, and I'm trying to format it as HFS+ journaled case sensitive encrypted, each time I try I get the following error:

"MediaKit reports block size error, usually caused by not being a multiple of 512."

This is a brand new drive, it has a GUID partition map with one partition, that was created by Disk Utility, and the disk passed a full hardware scan from Drive Genius.

Normally when I get an error I can google it, but this particular error only gives me links to RAID problems, and I'm not doing anything with RAID.

What determines the block size? I did not get an option to set it anywhere that I could see.

How do I fix this error and get my drive encrypted?

iMac, Mac OS X (10.7.4), 27" iMac

Posted on Jun 12, 2012 3:38 PM

24 replies

Aug 3, 2012 2:26 PM in response to Bart Busschots

I ran into this problem myself and found a workaround. I luckily had another disk that was already formatted with CoreStorage HFS+ Journaled Encryption.

I simply used the dd command to copy the headers from one disk to the other:

1. Unmount the destination disk

2. Use dd to copy from the working to destination disk:

$ sudo dd if=/dev/disk2 of=/dev/disk12 bs=4096

Note: I was able to Ctrl+C this command after a few minutes since the disk headers were long since copied by then. Otherwise it would have taken a day.

3. Mount the destination disk, notice that CoreStorage is now enabled

4. Erase the CoreStorage partition and set a new password.

RKGer

Level 1

0 points

Sep 19, 2012 7:10 AM in response to Bart Busschots

I ran into the same issue. I have an Intenso Memory Center 3 TB with USB 3.0. When attempting to either format the drive with Mac OS Extended (Journaled, Encrypted) or to encrypt an unencrypted partition, the disk utility returns the same error message as reported in the original post of this thread.

Carbon Copy Cloner did not solve the problem for me, I still get the same message from there. Using dd for this task as indicated by jeremiahrossini is a bit too cowboyish/insecure for my taste.

I hope Apple fixes this issue soon!

RKGer

Level 1

0 points

Sep 20, 2012 8:06 AM in response to Bart Busschots

The problem seems to be fixed with the new 10.8.2 update. I can encrypt my drive now.

Sep 22, 2012 1:04 AM in response to RKGer

You are so right. Thank you for the heads-up on this.

I can confirm that 10.8.2 does indeed address this long standing issue and that ML now supports Advanced Format 4K sectors for encryption.

RESOLVED!!!

Sep 24, 2012 5:19 PM in response to Bart Busschots

have just purchased Western Digital 3TB My Book Essential external drive as my new Time Machine back up - and surprise - disk encryption fails with this error.

Currently on Lion 10.7.5 - if I 'upgrade' to Mountain Lion 10.8.2 will this solve my problem? I'm not seeing a lot of comments in this thread or others about this with 10.8 so has it been solved for 10.8??

Seems like I am screwed as far as using this drive as my back up for the moment.

Sep 24, 2012 5:23 PM in response to RKGer

Right.... so now I have to shell out 30 clams and stuff around for a couple of hours while I upgrade to Mountain Lion jsut to get a fix for this bug. Way to go Apple...

Sep 24, 2012 6:28 PM in response to Bruce Mckay1

It is not a bug ... it is a new standard that Apple were late to the table with but now they are there.

As I said 10.8.2 now supports this, 10.8.1 didn't.

bgrupczy

Level 1

0 points

Dec 19, 2012 1:57 PM in response to Grant Ireland

Any word on when this fix is getting applied to 10.7?

Mar 25, 2013 10:52 AM in response to bgrupczy

I doubt that they will upgrade 10.7 for this since development of the OS is now ceased and in security maintenence mode.

But you can always try to send feedback and cross your fingers.

-aj

"MediaKit reports block size error" when formatting drive