5 Free and Easy Ways to Format Your 'C' Drive

Format 'C' to delete everything on your primary hard drive

A computer’s hard drive.
WLADIMIR BULGAR/Getty Images

To format C means to format the C drive, or the primary partition that Windows or your other operating system is installed on. When you format C, you erase the operating system and other information on the C drive.

Unfortunately, it's very much not a straightforward process to format C. You can't format the C drive like you can format another drive in Windows because you're within Windows when you perform the format. To format C from within Windows would be like lifting a chair in the air while sitting on it — you can't do it.

The solution is to format C from outside of Windows, meaning you need a way to format a drive from somewhere other than your Windows installation. The easiest way to do this is to boot from an operating system (with formatting abilities) via a CD/DVD/BD drive, flash drive, or floppy drive.

While that all might sound very complicated it's actually quite easy to do. Below are several completely free ways to format your C drive, each of which we've linked to extensive instructions.

If you're trying to format your C drive because you want to replace or reinstall Windows, you do not need to format C ahead of time. Formatting is done automatically during the Windows installation. Skip this article entirely and instead learn how to do a clean install of Windows.

Formatting your C drive does not permanently erase the data on the drive. If you want to completely erase the information on the C drive, see No. 5 below: Wipe the Drive Clean With Data Destruction Software.

01
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Format C From a Windows Setup Disc or Flash Drive

Screenshot showing how to format C from a Windows 10 setup disc
Format C From the Windows 10 Setup Disc.

The easiest way to format C is by completing part of a Windows installation. It's not easiest as far as the number of steps goes, but since most of us have a Windows Setup DVD or flash drive lying around, we have easy access to a means to format drives outside of Windows.

You can only format C this way using Windows 10, Windows 8, Windows 7, or Windows Vista installation media. Keep reading if you only have a Windows XP disc.

However, it doesn't at all matter what Windows operating system is on your C drive, including Windows XP. The only requirement is that the setup media needs to be from a newer version of Windows.

Feel free to borrow a friend's disc or flash drive if you'd like to try this method. Since you won't be installing Windows, you don't need to worry about having a "valid" copy of Windows or a product key.

02
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Format C From a System Repair Disc

Command Prompt in System Recovery - Format C
Command Prompt in System Recovery (Windows 7 System Repair Disc).

If you don't have access to Windows installation media, but you do still have access to a working copy of Windows 10, Windows 8, or Windows 7, you can create a System Repair Disc or Recovery Drive (depending on your version of Windows) and then boot from that and format C from there.

You can only format C in one of these two ways if you have access to Windows 10, 8, or 7 to create the media. If you don't, find someone who does and create the repair disc or flash drive from their computer.

A Recovery Drive or System Repair Disc can format a C drive that has any Windows operating system on it, including Windows XP, or Windows Vista.

03
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Format C From Recovery Console

Screenshot of the Windows XP Recovery Console for formatting the C drive
Windows XP Recovery Console.

If you have a Windows XP Setup CD, you can format C from the Recovery Console.

The biggest caveat here is that you must also have Windows XP installed on your C drive. However, if you don't have access to a newer version of Windows, this option may be your best bet.

This Recovery Console method to format C also applies to Windows 2000. Recovery Console does not exist in Windows Vista or later, nor does it exist in Windows ME, Windows 98, or earlier.

04
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Format C From a Free Diagnostic & Repair Tool

Picture of a CD that reads bootable repair DVD
Burnable Diagnostic DVD. Original Photo © chidsey - http://www.sxc.hu/photo/862598

Several free, bootable, CD/DVD based diagnostic and repair tools exist that have been put together by PC enthusiasts and companies other than Microsoft.

This will be your best option to format C if you don't have access to any kind of Windows install media and can't get access to a newer version of Windows to create a repair disc or recovery drive.

Any of these tools that have formatting capabilities will be able to format C without a problem.

At the moment, the link above goes directly to the Ultimate Boot CD site, one of several programs that allow formatting from a bootable disc. We'll update this link to a list of such programs soon.

05
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Wipe the Drive Clean With Data Destruction Software

Screenshot of DBAN formatting C
DBAN.

Data destruction software goes a step beyond formatting C. Data destruction software truly destroys the data on a drive, returning it to the essentially the same state it was in after leaving the hard drive factory.

If you're wanting to format C because you want to make sure everything on your primary drive is permanently erased, you should wipe your hard drive using these instructions.