"MediaKit reports block size error" when formatting drive

Question

"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

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Answer 1

Jun 13, 2018 2:24 PM in response to Bart Busschots

I think I may have found a solution. If you have Carbon Copy Cloner, you can use Disk Center to encrypt volumes. I was getting the same complaints from the OS, so I tried CCC and it seems to work! It's not comeplete yet (claiming 70 hrs for a 3 TB drive), but I haven't gotten the inital warnings like I did using Mac OS. I'll report back if I get a failure.

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Answer 2

Linc Davis

Level 10

209,547 points

Jun 12, 2012 4:58 PM in response to Bart Busschots

That sounds like a problem with the drive's firmware.

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Answer 3

Jun 13, 2012 1:45 PM in response to Linc Davis

Is there any way I could test the firmware? I can successfully format the drive to regular HFS+, so I don't think I have enough evidence to demand a replacement from Seagate just yet.

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Answer 4

Linc Davis

Level 10

209,547 points

Jun 13, 2012 1:48 PM in response to Bart Busschots

That's a question only Seagate can answer. In general, their external drives are not well regarded on this site.

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Answer 5

Jun 13, 2012 1:50 PM in response to Linc Davis

It's not an external drive - bare disk used through a Freecom "toaster". It was to be my new backup disk, but there is no way I can use an unencrypted disk for backup.

I guess I'll start the RMA process and see how far I get.

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Answer 6

Linc Davis

Level 10

209,547 points

Jun 13, 2012 2:14 PM in response to Bart Busschots

Do other drives work in that dock?

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Answer 7

Jun 13, 2012 2:18 PM in response to Linc Davis

Yup - including a slightly older model 2TB Seagate Barracuda (the same make, model and size as this problematic drive), which was successfully formatted to HFS+ journaled case sensitive encrypted using the dock, and to which I back up weekly through that dock.

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Answer 8

Jun 17, 2012 9:32 AM in response to Bart Busschots

This is a problem with new drive that have 4K block sizes. It only affects encryption. Apparently Apple are on the case. See https://iomega-eu-en.custhelp.com/app/answers/detail/a_id/28667

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Answer 9

Jun 21, 2012 12:22 PM in response to Ian Hill-Smith

This does indeed seem to be the problem.

Before you replied I RMAed the Seagate disk assuming it to be faulty, because, well, 4k is a multiple of 512b and all. Today, my new WesternDigital disk arrived - it gives the IDENTICAL error. The changes of two disks from two vendors both being faulty seem low, so I think we can safely say OS X has a nasty security bug that has been languishing for some time.

It seems the only way I can protect my backups is to use 3rd party softeware, or to find an old 2TB disk somewhere that still has 512b blocks rather than 4k blocks.

Hopefully Apple get this bug fixed soon, and hopefully others will find this post when they google the error message and at least understand that their disk is probably fine.

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Answer 10

slacer2d

Level 1

0 points

Jul 11, 2012 12:09 PM in response to Bart Busschots

I have the same issue while I try to encrypt my Timemachine backup with the Intenso Memory Center 3TB. This is a crazy bug I think. Know anyone that in Mountain Lion the problem will be solved?

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Answer 11

slacer2d

Level 1

0 points

Jul 11, 2012 1:26 PM in response to slacer2d

I tried a little bit more on the terminal. The bug seems to be in Core Storage. Here my output when I tried to convert the volume:

sh-3.2# diskutil cs convert /dev/disk4s2 -passphrase

New passphrase for converted volume:

Confirm new passphrase:

Started CoreStorage operation on disk4s2 Backup

Resizing disk to fit Core Storage headers

Creating Core Storage Logical Volume Group

Attempting to unmount disk4s2

Switching disk4s2 to Core Storage

A problem occurred; undoing all changes

Undoing creation of Logical Volume Group

Reclaiming space formerly used by Core Storage metadata

Error: -5308: MediaKit reports block size error, usually caused by not being a multiple of 512

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Answer 12

Jul 29, 2012 1:10 AM in response to slacer2d

There seems to be a known bug of encryption of disks with Device Block Size of 4k (4096 Bytes) in at least Lion and Mountain Lion. The error seems to be something like this:

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

You can check your device block size in Terminal with

diskutil info /Volumes/YOUR_VOLUME_NAME

If you are experiencing this bug, too, please submit a bug report to apple in some way to increase the pressure to fix it!

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Answer 13

Jul 30, 2012 1:43 PM in response to tbhunderbird

Thanks for the Terminal command - that proves that this is indeed a bug:

Device Block Size: 4096 Bytes

And still getting the same error on Mountain Lion that I was on Lion.

This is a bloody disgrace!

Modern disks are 4K - if you buy a big disk, that's what you're gonna get. To proudly claim disk encryption as a feature and then fail to deliver on standard disks is dishonest at best.

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Answer 14

slacer2d

Level 1

0 points

Jul 30, 2012 1:53 PM in response to tbhunderbird

My drive seems also 4K blocks:

Total Size: 3.0 TB (3000592982016 Bytes) (exactly 5860533168 512-Byte-Blocks)

Volume Free Space: Not applicable (no file system)

Device Block Size: 4096 Bytes

Imho all disks larger than 2 TB have 4K Blocks, isn't it?

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Answer 15

Jul 30, 2012 1:56 PM in response to slacer2d

I've been looking for 2TB disks with 512b blocks rather than the new 4k block size, but I can't find any. If anyone knows a source I'd really appreicate it. Today my backups out-grew my old disk. I bought a new bigger disk a few months back and ran into the problem. I really had hoped Apple would take a security problem seriously, and that the fix out be out before my old disk ran out of space.

Now I have the Hobson's choice of no backups or insecure backups - oh joy! Thanks Apple!

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