Windows 7 Forums
Welcome to Windows 7 Forums. Our forum is dedicated to helping you find support and solutions for any problems regarding your Windows 7 PC be it Dell, HP, Acer, Asus or a custom build. We also provide an extensive Windows 7 tutorial section that covers a wide range of tips and tricks.

Windows 7: External HDD became unallocated

08 Jun 2015   #31


If you are happy with the 3tb now then you can leave it if you purposefully created the 100mb partition, even though it's not really needed for a later OS install - Unless you have a purpose in mind.

My System SpecsSystem Spec
08 Jun 2015   #32

Windows 7 Ultimate x64

But i dont see any 100mb partition in the last screen i show, can you show me where you seeing 100mb partition in last screen?

I only see 3 partitions in last screen in Partition magic, 97gb-743gb-1953gb.
My System SpecsSystem Spec
08 Jun 2015   #33

Windows 7 Ultimate x64

Yes ever time i installed the OS in EFI i used option in installation to delete the partition i wanted to use then it become unallocated space and installer created GPT EFI OS fine. I done that to my win 8.1 and win 10 preview already.

So i think i will have no problem letting things like is now right?
My System SpecsSystem Spec

08 Jun 2015   #34


Well there's no problem creating the small partition, but again you shouldn't count on it for OS but instead during an install delete it and the next big partition and create a new partition using the installer which will decide how it wants the System configured.

This will most likely be the case if you ever install to the disk because there is a hidden MSR partition which may not be preserved (and likely shouldn't) and the current configuration hasn't a large enough boot partition to replicate the 128mb EFI SYstem partition.
My System SpecsSystem Spec
08 Jun 2015   #35

Windows 7 Home Premium 32 bit

Quote   Quote: Originally Posted by chummy View Post
Now i get confused, Greg said to remove some useless 100mb system partition and Jumanji say to create GPT with this 128mb partition, whats wrong here?

In the last screen take from win7 there is nothing about 100mb partition...
The 100GB partition is just like any other partition. It is not a system reserved partition. It is not created by the system. You want to have it or not is your choice.

If you are talking of future proof, you should have the 128MB M(icrosoft) S(ystem) R(eserved) Partition. On any internal GPT drive Windows will create this 128MB MSR partition.(Also MicroSoft Reserved)

If your internal drive does not have the 128MB MSR partition, you should atleast do a diskpart clean - This can be done by HDD LLF format Tool too - and then initialise the drive as a GPT drive and create other partitions using Windows Disk Management. Windows will automatically create this 128 MB MSR but may hide it to the user or show it as a RAW partition.

"Formerly, on disks formatted using the older MBR partition layout, certain software components used hidden sectors of the disk for data storage purposes. One example of this is the Logical Disk Manager (LDM), which, should the disk be converted from a basic disk to a dynamic disk, would store metadata in a 1 MB area at the end of the disk which was not allocated to any partition.[2]
GPT formatted disks and the UEFI partition specification do not allow hidden sectors[citation needed]. Microsoft reserves a chunk of disk space using this MSR partition type, to provide an alternative data storage space for such software components which previously may have used hidden sectors on MBR formatted disks. Such software components, for example LDM as mentioned above, can create a small software-component specific partition from a portion of the space reserved in the MSR partition"

Microsoft Reserved Partition - Wikipedia, the free encyclopedia

"What is a Microsoft Reserved Partition (MSR)?

The Microsoft Reserved Partition (MSR) reserves space on each disk drive for subsequent use by operating system software. GPT disks do not allow hidden sectors. Software components that formerly used hidden sectors now allocate portions of the MSR for component-specific partitions. For example, converting a basic disk to a dynamic disk causes the MSR on that disk to be reduced in size and a newly created partition holds the dynamic disk database."

128MB is nothing much to lose but you will be safe under any circumstances today or tomorrow..
My System SpecsSystem Spec
09 Jun 2015   #36

Windows 7 Ultimate x64

Ok i made the process now with diskpart clean and recreated all partitions in disk manager and now PW show the 128mb.

External HDD became unallocated-finalmente.png

Hope is alright now.

My System SpecsSystem Spec
09 Jun 2015   #37

Windows 7 Home Premium 32 bit

OK, you are good to go.

Now you can put the drive in the enclosure and check how it looks like in Windows Disk Management and Partition Wizard.

To my mind it shouldn't make any difference. I may be wrong. Seeing is believing. Post both the screenshots.

(We are also - particularly me - learning . I don't have a >2TB drive, I do all my GPT experiments on a 750GB Seagate FreeAgent GoFlex external drive. I am waiting for a truly GPT formatted >2TB external drive. Only Toshiba has come out with such a drive recently but still not available. When I checked the Toshiba site when I was in USA last month, it said likely shipping date 28 May 2015. I was leaving USA on 17th May. So I did not order.)

But whatever, if you want to use it as an internal drive be it so and use it so. Don't keep shifting it from internal to external and vice versa. You are likely to ruin your drive faster than otherwise. My two cents or should I say pennies?
My System SpecsSystem Spec
09 Jun 2015   #38

Windows 7 Ultimate x64

Probably you're right, i reverted to USB to test in win8.1 first and windows dont read the partitions, i look inside disk manager and it read a entire 2.7tb GPT partition.

The main reason is than in USB 2.0 this HDD is only doing transfer rate of 25MB/s, when i change to internal at Sata2 it go around 140-170MB/s, way faster. But since it dont works when change USB to Sata and vice versa i should avoid it then.
My System SpecsSystem Spec
10 Jun 2015   #39

Windows 7 Home Premium 32 bit

What I was interested was a)whether you can see the full 3TB on the Windows 8 machine and you are able to read and write to it ? b) Screenshots of Windows Disk Management and PW. USB2 transfer rate of 25MB/s is normal.

I presume the answer to the first question is Yes though your statement "windows dont read the partitions" is a bit confusing. Without a read/write how did you find the transfer rate?
My System SpecsSystem Spec
10 Jun 2015   #40
Layback Bear

Windows 10 Pro. 64/ version 1709 Windows 7 Pro/64

jumanji thank you for all your help.

You do ask some good questions.

Without a read/write how did you find the transfer rate?
It is very confusing to me also.
My System SpecsSystem Spec

 External HDD became unallocated

Thread Tools

Similar help and support threads
Thread Forum
External HD - Partition Unallocated
Dear All, I believed that I have accidentally unallocated the partition of my 1TB external hard drive. Not sure if this was the cause, but a day ago, I intended to migrate my existing data in 1TB external hard disk to another 4TB external hard disk. Then, I came across the Computer...
Hardware & Devices
How to Fix external HDD bad disk, unallocated, not initialize
Hi. I have a WD 500gb external HDD. I can't access it anymore and I really don't know how to fix it. It won't show in My Computer but I can still see it Disk Management. The files are not important since I have a copy of it, I just really need to fix my external. Any help would be much appreciated....
Hardware & Devices
My external hard drive is unallocated
Hi guys, I was checking for errors on my WD HD the other day due to low speed and leave it alone but my mother unplug it inadvertently! Clearly it's unallocated now. I've read a lot of posts especially those sent by jumanji (Windows 7 Help Forums - View Profile: jumanji) and apply almost all...
Unallocated space on new 4TB external HDD, how can I name this volume?
see attached. I've just bought this new 4TB HDD (disk 2) to replace other 500GB (disk 3). After having viewed a few tutorials on YouTube I did "Shrink Volume" on the primary partition (when that's all there was) and created the 1.6GB space. When right clicking on the Unallocated space, all...
General Discussion
External drive was readable, now it is unallocated?
Hi all, The situation is fairly simple. This morning I : 1: Unmounted and unplugged my external drive which is a WD My Book Essential 2TB 2: Took it to a colleague and tried to connect it to his IMac4 which has OS X 3: Nothing worked, we could see the drive but couldn't access it even with...
Hardware & Devices

Our Sites

Site Links

About Us

Find Us

Windows 7 Forums is an independent web site and has not been authorized, sponsored, or otherwise approved by Microsoft Corporation. "Windows 7" and related materials are trademarks of Microsoft Corp.

Designer Media Ltd

All times are GMT -5. The time now is 04:30.
Twitter Facebook Google+ Seven Forums iOS App Seven Forums Android App