Windows normally installs itself to a single partition on your hard drive. However, you can split your hard drive into several different partitions and store your data files separately from your system files.

This can be particularly useful when it comes time to upgrade or reinstall Windows — you can perform a clean install, wiping away your personal files from the main drive and leaving the secondary drive as-is with your personal files.

When Installing Windows

To create a separate data partition while installing Windows 7 or Windows 8, you’ll need to select the Custom installation option. Go through the installation process normally until you reach the “Which type of installation do you want?” screen and click the Custom option.

On the next screen, click the Drive options (advanced) link.

Create several partitions by clicking the New button and entering a size for each partition.

When you’re happy with your partition sizes, select the partition you want to install Windows to and click the Next button. Windows will install to that partition. The space on the other partition will be available as its own separate drive letter in Windows.

After Installing Windows

RELATED: How to Manage Partitions on Windows Without Downloading Any Other Software

There’s a good chance you already have Windows installed to a single partition on your hard drive. If so, you can resize your existing system partition to make free space and create a new partition in that free space. You can do all of this from within Windows.

You’ll need to access the Disk Management tool from within Windows to do this. On Windows 8, press Windows Key + X or right-click in the bottom-left corner of your screen and select Disk Management. On Windows 7, press the Start button on your keyboard, type manage disks into the Start menu’s search box, and press Enter.

In the Disk Management window, right-click your C: partition and select Shrink Volume.

Warning: Before messing with your partitions, you should always ensure you have backups of your important files. You shouldn’t encounter any problems while doing this, but data loss is always a potential threat when modifying your partitions.

Enter the amount of space you want to shrink the partition by, in MB. For example, if you want a 100 GB data partition, enter 102400 into the box and click the Shrink button.

Of course, you must have enough free space on the partition to shrink it. If you only have 20 GB of free space, you won’t be able to shrink the partition by more than 20 GB. If you need to free up space but don’t want to delete any files, you may want to temporarily copy them to an external hard drive, delete the originals, and copy the files back over to your data partition afterwards.

After the process completes, right-click inside the Unallocated space and select New Simple Volume to create a new partition from the unpartitioned space.

Follow the wizard, assigning your desired drive letter to the new partition. When the process is complete, you’ll have a separate data partition.

Using Your Separate Data Partition

To make the most of your separate data partition, store your personal data files on it. To make this easier, you can move your user data folders — your Documents, Downloads, Music, Pictures, and Videos directories, for example — to your external hard drive by right-clicking each folder in Windows Explorer (or File Explorer on Windows 8) and using the options on the Location tab.

There’s no point in installing most programs to the data partition, as they’ll have to be reinstalled if you ever reinstall Windows. However, some programs can be placed on the data partition and used even after you reinstall Windows. For example, Valve’s Steam service and Blizzard’s games all allow you to run their games from a folder without having to download and install them after reinstalling Windows. Just run the .exe file from the folder and you’re good to go.

When you reinstall Windows, you’ll be able to format your system drive cleanly and have all the files on your data partition in the same place. If you’re dual-booting several versions of Windows, each of them can use the data on the separate data partition without accessing each other’s system partitions.

RELATED: 7 Tips For Using Multiple Hard Drives With Windows

Of course, you can always get a separate data partition by adding a second hard drive to your computer. A second hard drive will appear just like a second partition in Windows Explorer or File Explorer, with its own drive letter.

Follow our tips for using a second hard drive with Windows for more ways to put a second partition or hard drive to use in Windows.

Is this something every Windows user should do? Well, probably not — especially now that Windows 8 offers an easy way to effectively reinstall Windows without losing your personal files, named “Refresh Your PC.” But, if you regularly reinstall Windows or dual-boot several versions of Windows, this can be a useful trick.

Image Credit: Jeff Kubina on Flickr

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Chris Hoffman is Editor-in-Chief of How-To Geek. He's written about technology for over a decade and was a PCWorld columnist for two years. Chris has written for The New York Times and Reader's Digest, been interviewed as a technology expert on TV stations like Miami's NBC 6, and had his work covered by news outlets like the BBC. Since 2011, Chris has written over 2,000 articles that have been read more than one billion times---and that's just here at How-To Geek.
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