Forum FAQ:Disk Topic Part 7 -The 100MB hidden partition created during the Windows 7 installation process
Thursday, June 17, 2010 8:33 AM
This partition is created for a few main reasons:
I. Bitlocker requires that the boot files and Windows files be separated. Also, this system partition may be used by utility software, such as backup problems, to support dual boot scenarios.
II. Protect against deletion. If files saved on system partition, it is easy to lose the boot files due to a format when reinstalling the operation system on system partition.
The drive received no drive letter as further protection against accidental deletion of the boot files.
When you boot from the DVD to perform a clean install of Windows 7, setup will create the 100MB system partition under the following conditions:
There is not an existing system partition on the machine
The system does not have 3 existing partitions
There is unallocated space on the disk for the extra partition
If you do not meet the conditions, such as if you do not have unallocated disk space for a new system partition, setup attempts to use the existing system partition for boot files. If no partition is currently marked active, setup sets one as active using the same process applied by Windows Vista setup previously.
A result of the above conditions is that the system partition is not created during upgrade installation or clean install from a previous system. In both of these cases there is an existing system partition, which is used for boot files. In these cases Windows 7 setup proceeds in the same way as Windows Vista setup.
System Image Backup will backup it automatically. (For, detailed steps please refer to " Windows Backup and Restore ")
4. How to delete this hidden partition?
Above all, it is not recommended to delete the hidden partition. If you would like to delete it when creating the system, refer to the part "When will the Windows 7 installation process create the 100MB hidden partition? " listed above to prevent installation process create it.
If you would like to delete that partition after installing Windows 7, you will need to manually create boot files on system partition first. Here are the detailed steps:
I. Start Windows 7, click Start button, type "CMD " (without quotation marks) into the Search box, right click on it and choose Run as administrator .
II. Type "bcdboot c:\windows /s c: " (It means copy the boot files of the system "c:\windows " to drive c . If system is not installed in c:\ you need to change the path).
You will get a message "boot files successfully created ".
III. Open Disk Management by inputting "diskmgmt.msc " in Search box, locate the main C:\ partition and mark that active instead of the hidden partition.