During installation Windows 7, 8 and Windows 10 create a special partition called " Reserved for the System ". This partition, to which Windows does not assign any letter, remains hidden and not visible in Windows Explorer.
One notices his presence by going to Disk Management, the administration utility that can be found from the Start menu search.
This private partition contains two important things
- The boot instructions of the computer, ie the Windows Boot Manager, loaded by the boot loader, which reads the boot data from the Boot Configuration Data (BCD) and which tells the computer to load Windows from the system disk.
- The files used for BitLocker encryption, if used to encrypt the disk.
In essence, the partition reserved for the system is essential if you want to use BitLocker encryption, which otherwise cannot work while the computer boot files saved in this partition could also be moved to the main Windows partition.
The size of the partition reserved for the system is rather small, just 100 MB on Windows 7 and 350 MB of space on Windows 8 or Windows 10 .
As said, it is created during the installation of Windows and you can notice a warning about it when you choose which partition to install the system on.
Specifically, you can read a message saying that to ensure that Windows works properly, it could create additional partitions for system files.
In general, this partition should definitely not be touched .
Windows keeps it hidden thus making it not visible to normal users who will not have any discomfort from its presence.
This partition, as mentioned before, is essential only for those who use Bitlocker, because it contains the decryption information of the main disk which, otherwise, should be saved on a different drive.
However, deleting it is not recommended.
If you really don't want this partition to be part of the drive, the ideal is to prevent it from being created .
Instead of creating a new partition in the unallocated space during the Windows installation, you can start the computer with a different program and with this create a new full partition that occupies all the unallocated space.
After this, during the installation of Windows, choose the created partition and continue.
Since Windows will not find space to create the partition reserved for the system, those files will be put on the main disk instead.
Parted Magic or GParted can be used as disk partitioning software which make this type of operation simple.
Without external programs instead, from within the installation of Windows, the procedure is more elaborate and described in these steps:
- Press Shift + F10 during Windows installation to open a command prompt window.
- Type diskpart in the command prompt window and press Enter.
- Create a new partition in the unallocated space using the diskpart tool.
So, for example, if there is only one disk in the computer and it is completely empty, simply write select disk 0 and then create partition primary to select the first disk and create a new partition using the entire unallocated space on the disk.
- Continue the installation process by selecting the newly created partition when asked to create one.
Removing the system partition after installing Windows is possible, but you really have to be careful.
You cannot simply delete it because the boot loader files would also be lost preventing the computer from starting and loading Windows.
To delete the reserved system partition, you must first move the boot files from the system reserved partition to the main disk and this is more difficult than it appears.
I have found some guidance on the subject, but personally I do not recommend it and I do not think it is useful to explain how to do it.
Changes should be made to the registry, copying various files between the units, updating the BCD archive and modifying some system settings, with the risk of compromising system stability.
This system partition may seem like an unnecessary waste of space, but it performs important functions for the general functioning of the computer and should not be touched at all, unless you choose not to have it when installing Windows.
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