On a fresh (custom) installation of Windows 7, where Windows 7 is installed onto a new hard disk with unallocated disk space (no partition or volume been defined yet), or when user attempts to create a new partition out of empty drive, the Windows 7 installer will create an additional partition with the size of 100 MB, and mark as System Reserved.
The 100 MB volume is labeled as System Reserved with NTFS file system, and System, Active, Primary partition attribute with no drive letter in Disk Management. The 100 MB system reserved partition is only available for Windows 7 Ultimate, Windows 7 Business and Windows 7 Enterprise editions. The 100 MB system partition is used primarily as BitLocker partition for BitLocker encryption. Additionally, it also holds the Windows Recovery Environment (WinRE) and boot files with boot manager for booting up the computer for troubleshooting when there is no Windows 7 installation DVD disc on hand.
For Windows 7 users who do not intend to use BitLocker, the 100 MB partition can be removed subsequently and easily in Disk Management, the built-in partition manager of Windows 7. However, users can stop and prevent the 100 MB partition from been created in the first place during installation of Windows 7, via several workarounds and tricks or hacks. This hack is slightly different from trick used to remove 200 MB partition in Windows 7 RC or Beta.
1. On the “Where do you want to install Windows?” partition screen of Windows 7 Setup, click on Drive options (advanced) to delete existing partitions and create a new partition.
2. Click OK when Install Windows wizard prompts with the following message:
"To ensure that all Windows features work correctly, Windows might create additional partitions for system files."
3. Select size of first partition, and click apply.
4. When try to create two partitions, three partitions should be created, a System Reserved System type partition (Disk 0 Partition 1) with 100 MB in size, and originally intended primary type partition (Disk 0 Partition 2) with allocated size now less than 20 GB, and unallocated space on Disk 0 with rest of space for creating third partition.
5. Now create third partition with rest of space, by selecting unpartitioned space and clicking apply.
6. Delete the Primary Partition created (Disk 0 Partition 2).
7. Click OK when prompted that “The partition might contain recovery files, system files, or important software from your computer manufacturer. If you delete this partition, any data stored on it will be lost.”
8. Disk space inside the partition deleted will now become unallocated space. Now, highlight System Reserved Partition, and click Extend. Assign the available disk space to the partition, and click Apply.
9. Click OK when prompted with “Extending a partition is not a reversible action. If you proceed, you will not be able to undo this action later.
10. Format both partitions by highlighting on the partition, and clicking Format.
11. Click OK when prompted with “The partition might contain recovery files, system files, or important software from your computer manufacturer. If you format this partition, any data stored on it will be lost.”
12. After finished formatting, the originally System Reserved Partition will now become normal system partition, and ready to install Windows 7. Proceed to install Windows 7 as usual.
2) Rename the first file, and hit either F2 or Enter.
