How to Shrink a Windows Vista partition and create space for a second partition on your drive:
The 250GB hard drive I’m using for this article contains both the partition that contains the Vista operating system and a “Recovery” partition. While this is not a large drive there may be enough free space (50GB should be more than enough) to accommodate Windows 10. If your drive is nearly full you may need to off load (move) some of your older less used data files (Documents, Music, Photos, Etc) to the USB drive if necessary.
In order to create space on the drive for Windows 10 we will use Vista’s Disk Management utility to “Shrink” the Vista partition which will result initially in “unallocated” space, and after formatting will be available for use when installing Windows 10.
After the Windows vista partition is shrunk / resized to make room for Windows 10 another baseline image backup of the entire drive will be created, this second baseline will be used as a starting point prior to installing Windows 10.
If Disk Management cannot create the space needed for Windows 10 then there may be unmovable / locked files located near the end of the partition. To solve this, a third party disk management utility can be installed which can overcome the issue of locked files.
1) Launch Disk Management, click Start / right click on ‘Computer’ and select ‘Manage’, give Vista permission to continue. Now click on the ‘Disk Management’ option located in the left column.
2) Right click on the Vista (C:) partition and in the drop down list select ‘Shrink Volume’.
3) The existing size of the Vista partition is 220GB (Decimal) and 225280 (Binary), from this we need to shrink it down to 180GB in order to create a 50GB Windows 10 partition.
4) Enter the value 51200 in the ‘Enter the amount of space to shrink in MB:’ box.
5) Click the ‘Shrink’ button to complete the process. Now you should see a 170GB Vista partition and 50GB of unallocated space.
At this point you could exit Disk Management and during the installation of Windows 10 select the “Unallocated” space for where you want to install Windows 10.
My preference is to create a partition, preformat it and assign a meaningful volume name (Example: Windows 10). This makes it an easy to spot and select which partition to use when selecting where to install Windows 10. Note: Hard disk users should perform a “Full” format of the unallocated space, Solid State Drive (SSD) users should use the default ‘Quick format’ option. Note that the drive letter assigned is of no consequence as after installing Windows 10 it will change to C:.
6) Create and format a new primary partition using the unallocated disk space with Vista’s Disk Management utility.
For added reliability with hard drives I always choose to perform a ‘Full’ format, SSD (Solid State Drive) users should choose the ‘Quick’ format option. Assign a meaningful volume name such as Windows 10.
The drive letter Vista assigns to the new partition is of no consequence as after Windows 10 is installed, it will always boot as C: and Vista will still boot as C:
7) At this point its time to create your second baseline backup. This is the backup you can use to reset your drive back to a pre Windows 10 installation state.
Verify that the entire drive: Vista partition, the empty Windows 10 partition, the Recovery partition and the Master Boot Record (MBR) and any other partitions that may be on your drive are included in the backup.
Start the backup and when completed you should have two image backups on your USB drive.
One note of caution, don’t forget to create Windows Vista partition only backups (System Backup option) on an “as needed basis” whenever you have installed new software or uninstalled some unwanted application in Vista. The Windows Vista partition can be restored from a system backup on an as needed basis.