Macrium Unformatted Partition-What is this?

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On a newly formatted drive, in Macrium I’m seeing 16MB of unformatted space.  Doesn’t show that in Disk Management.  What the heck ?

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It’s the MSR partition, which isn’t strictly required but is, by default, standard on GPT-style disks.

 

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Is it an SSD? Could be alignment of the standard partition installed by the manufacturer – they don’t care about losing a few MB if it makes imaging easier.

cheers, Paul

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Paul
Aren’t those alignment partitions at the logical beginning of the drive.

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Just because you don't know where you are going doesn't mean any road will get you there.

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There are no alignment partitions, the partitions themselves are aligned.

Further to me post, even an HDD could have odd space if it makes the manufacturers job easier.

cheers, Paul

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Yes of course I miswrote. Would not the alignment space be at the logical beginning of the drive?
I think this is hard to even see from the windows disk management gui at least on my SSD.

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Just because you don't know where you are going doesn't mean any road will get you there.

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Alignment is on 4k boundaries so you wouldn’t see the loss of space (less than 4k).
It seems more likely the manufacturer is being lazy and doesn’t care about wasting a little bit of space – it could just be down to the person who wrote the installation routine.

cheers, Paul

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wavy

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Thanks folks.  For the record, the drives (disk 1, disk 2) are HDDs.  The boot, disk 0, is an SSD

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Mike, let me reiterate this has nothing to do with alignment, OEM choices, or SSD vs HDD. As I said earlier, it’s a normal MSR partition. If you let Microsoft initialize a new disk with GPT-style partition table, it will always include a MSR partition, whether it’s needed or not. IME, most (if not all?) non-Microsoft partition managers will not add a MSR partition.

If you were to check your partitions with a real partition manager, you’ll see it’s an actual partition. Macrium Reflect is not a partition manager, and Windows’ Disk Management only pretends to be one.

Here’s how your partitions would look in Aomei Partition Assistant with that space as an MSR partition vs. as unallocated space:

Here’s how Macrium Reflect displays the MSR partition vs. unallocated space:

And if you were to look at the bytes of the actual partition table, you’d also see the table entry for an actual partition:

As I said, this is the result of letting Microsoft do your partitioning. If you don’t like it, use a real partition manager to delete the partition, and next time use a real partition manager to begin with.

OTOH, the space used is inconsequential, and it will be easier to enable Bitlocker if you decide to do so in the future.

 

3 users thanked author for this post.

Mike, Elly, wavy

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Thanks DG1261 for a great explanation. I agree 16mb is not worth worrying about….just a curiosity  for me since I was under the impression  that the MSR was only on OS disks. I wonder if using diskpart would make the MSR as well.  Again, just wondering.
Thanks everyone.

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Mike wrote:

I was under the impression that the MSR was only on OS disks.

The Wikipedia link I posted earlier says: “Microsoft expects an MSR to be present on every GPT disk, and recommends it to be created as the disk is initially partitioned.”

Mike wrote:

I wonder if using diskpart would make the MSR as well.

I just tried a test in a VM, and yes it does. If you use diskpart to initialize a new disk as GPT, it will automatically add a MSR partition.

It’s only the initialization step that adds the MSR. If the disk is already initialized without an MSR by other means, diskpart or Disk Management will create or delete partitions without regard to whether there is any MSR partition.

I don’t use an MSR, but my understanding is it is for use with Bitlocker or dynamic disks. Thus, in most systems it is superfluous and can be eliminated if desired. I presume it is put there by Microsoft just to make things easier if the user should decide to enable dynamic disks or Bitlocker later on.

 

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Mike

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