So what? If you don't want it you can partition the drive prior installation making the first or only partition as primary and active. This way you prevent that hidden partition.
Windows 10 Insider Preview (x64) - Build 10162 - BIOS/MBR View attachment 36824 - UEFI/GPT View attachment 36825
If you boot to the iso image, and select for a clean install you'll get a chance to format c:\, and if you simply delete all the partitions on the drive where you want to install Windows, or just delete the partition you want to be your c:\ drive, and leave the partition unallocated (raw) after you delete it--then hit the "Next" button...what happens then is that the Win10 install routine automatically sizes and installs and correctly formats the recovery partitions before it begins to copy files over in the beginning of the install. I did that with 10162 and Windows automatically gave me a 450 MB hidden recovery partition, and a 100MB hidden EFI partition, so I can't imagine why anyone might want to try and install Win10 without those hidden recovery partitions (as they take up very little space on the drive.) Also remember that to get Win10 install to EFI you need to start with a gpt partition and have secure-boot enabled in the bios. Then follow the above steps for the Win10 EFI install. I've noticed that in installing to an unallocated partition (which windows automatically will format and partition if allowed to), the hidden partitions come before the c:\ partition begins. If installing to an MBR drive the 450 MB hidden recovery partition is installed on the tail end of the c:\ System drive instead of before it, and of course there is no additional 100MB EFI partition in that case. At least, this is what occurred for me with 10162...
The System Reserved Partition on BIOS/MBR based systems is the partition marked as Active and is home to the core Windows boot components like bootmgr and the BCD. It also is generally home to the Windows RE image (winre.wim) too. Windows stores these items on a separate partition in order to keep them safe and more secure from accidents that may occur on the primary OS partition and ensure one can still at least boot to WinRE. In the UEFI/GPT world, the EFI System Partition (ESP) and the WinRE Partition are the technical equivalents to the System Reserved Partition on a BIOS/MBR system. The ESP is required for booting on any UEFI/GPT based system.
Great points...thanks for the clarification... Yep, the partitions are so small I wonder why anyone would object to them, especially in light of their obvious purpose...
No problem. Glad to share the info. I also wonder why people want to delete them too. Maybe through some education that will change their minds.
By default the GPT table contains space for defining 128 partitions. But if you want to define more partitions, you can allocate more space to the table.