If you’ve ever installed Windows yourself, you may have encountered a situation where Windows Setup tells you that it is about to create a system-reserved partition or an EFI system partition for system files. The size of this section is 100 MB. Exact Query:
To ensure that all Windows functions are working correctly, Windows can create additional partitions for system files.
You only get this dialog and this additional system partition in certain scenarios. Typically, if you click OK at the prompt, your sections will look like this:
The System Reserved partition is created using a disk that uses an older BIOS and MBR (Master Boot Record) partitioning scheme. The size of the partition reserved by the system is 100 MB, but the data size is only 30 MB.
If you are using a computer with UEFI BIOS and GPT partitioning scheme (GUID Partition Table), then it will create an EFI system partition. However, the size is exactly the same.
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So what exactly is on this special section, do you really need it and how do you remove it? Let me answer these three questions separately.
What is System Reserved / EFI (100MB) partition?
If you go in and really look at what is stored in this section, you will see something like this:
Basically the folder contains the following files and folders:
– Boot – System Volume Information – bootmgr – BOOTSECT.bak – $ RECYCLE.BIN
So what’s all this for? The baffle has two main functions. First, it stores the boot manager code and the boot configuration database. Second, it stores the startup files required for BitLocker Drive Encryption. If you end up using BitLocker to encrypt your entire hard drive, you don’t have to re-partition the system to enable it. If you never plan to use BitLocker, then you will never need this special partition.
Do you need a reserved partition for the system?
The short answer is: if you already have it, then YES you need it. You cannot uninstall it because it contains the boot files required to boot Windows. Unfortunately, once it was created, it is no longer possible to get rid of it. If you want to have a system without an additional partition, you can only do this during the Windows installation process.
How to remove the system reserved partition?
As I mentioned earlier, you cannot uninstall it on an existing Windows installation. However, you can choose not to create it when installing Windows on a new system. There are several ways to do this.
1. Use existing partitions – Windows will create a system-reserved partition only if you create a new partition on a disk where no partitions have been created. It will also create it if you delete all current partitions on the disk and then create a new one. If you want to avoid an extra partition, just use the partitions that are already on the system. To perform a clean install, you can simply format the existing partition instead of deleting all partitions.
2. Partitioning before installation. The second way to do this is to use a third-party tool or another Windows installation disc (such as Windows 10 or Windows 7) and partition the drive before starting Windows Setup. If you only have Windows installation media with you, there is a way to do this, but it takes a little more work.
Usually, when you get to the first screen in Windows Setup, press SHIFT + F10 to open a Command Prompt window. This works in Windows 7, 8, and 10 installations. Then enter the following commands, pressing Enter after each line.
diskpart select disk 0 create primary partition exit
Then just proceed with the Windows setup and select the partition that you create with the commands above. Since this is an existing partition, Windows will not create a system-reserved or EFI partition.
3. Windows installation trick. The last way to do this is with a little Windows setup trick. Typically, delete all partitions and then create a new one during installation. It will inform you that it is going to create additional sections and you will click OK. You now have what I showed in the second screenshot in this post above.
At this point, you simply delete the primary partition and you will be prompted something like “This partition has system files and if you delete this partition, all data will be lost.” Click “OK”, after which only the system-reserved partition and unallocated space will remain.
Now click on the System Reserved section and click on Extend. This will make the System Reserved partition the size of the entire disk, not 100 MB. Finally, you have to click “Format” to convert the system reserved partition to a normal partition.
Hopefully this clears up a bit what a system reserved or EFI system partition is for and how you can manage it. Enjoy!
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