How To Format C Drive

5 Ways to Format C Drive in Windows 10, 8, 7, Vista, & XP

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 but it's actually quite easy to do. Below are several completely free ways to format your C drive, each of which I've linked to extensive instructions for:

Note: 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 see How To Clean Install Windows.

Important: 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 Option 5 below, Wipe the Drive Clean With Data Destruction Software.

Format C From a Windows Setup Disc or Flash Drive

Format C From the Windows 7 Setup Disc - Format C
Format C From the Windows 7 Setup Disc.

The easiest way to format C is by completing part of a Windows installation. It's not easiest as far as 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.

Important: 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.

How To Format C Using a Windows Setup DVD or Flash Drive

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. More »

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.

How To Format C From a Recovery Drive or System Repair Disc

Note: 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. More »

Format C From Recovery Console

Windows XP Recovery Console - Format C
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.

How To Format C From Recovery Console

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. More »

Format C From a Free Diagnostic & Repair Tool

Burned Diagnostic DVD - Format C
Burned Diagnostic DVD. Original Photo © chidsey -

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.

Download Ultimate Boot CD (UBCD)

Note: 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. I'll update this link to a list of such programs soon. More »

Wipe the Drive Clean With Data Destruction Software

DBAN - Format C

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.

How To Wipe a Hard Drive

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. More »

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