Formatting a drive in Windows 8.1 is handled by the Disk Management utility. The same process applies to both hard disk drives, or HDDs, and solid state drives, or SSDs. After deleting the volumes, or partitions, on the drive, you can format the drive and create new volumes. Remember to back up any files you want to keep before starting this process. Deleting and formatting destroys all data on the drive.
Back up all data on the drive you want to format. Tap the "Search" icon on the Windows Start screen and type "format disk" in the Search field. Select "Create and Format Hard Disk Partitions." The Disk Management utility opens.
Click the drive that you want to format. Note that in most cases "Disk 0" is the drive with the Windows operating system on it. If this is the disk you want to format, you should reinstall Windows instead.
Click the "Action Menu," select "All Tasks," and then click "Delete Volume..." Double-check that you have the right drive selected. The selected drive is shaded with diagonal stripes.
Click "Yes" at the warning that all data on the partition will be deleted. After a few seconds, the volume is deleted. The drive is now listed as unallocated in the Disk Management window.
Select the drive you are formatting if it isn't already selected. Click the "Action" menu, then "All Tasks" and "New Simple Volume." The New Simple Volume Wizard opens. Note that if the disk is part of an array, advanced users will have additional options like creating a new spanned volume, striped volume, mirrored volume or RAID-5 volume.
Click the "Next" button in the New Simple Volume Wizard so you can specify your preferences.
Specify how much space should be used in the new volume by entering a value in the text field. If you are creating only one volume or partition in the drive, this number should be the same as the maximum disk space displayed above. Click "Next."
Select a drive letter that you would prefer the computer to use for this drive. If you don't want a letter assigned, click the "Do Not Assign a Drive Letter or Drive Path" option. Advanced users may also prefer to mount the drive in an empty NTFS folder. Click "Next."
Select a file system for the volume. Your options are ExFAT or NTFS. Use ExFAT if you're going to share files with a Mac computer; otherwise, NTFS is the better choice. Unlike its predecessors, ExFAT can support the same volume sizes as NTFS -- up to 256TB. However, it's not as robust as NTFS and doesn't support file system-level encryption and built-in compression. Mac computer's can't write files to an NTFS drive.
Select the "Perform a Quick Format" option if the drive doesn't contain any private information, or if you're using the drive for your personal use. A Quick Format takes only a few seconds, but the data it leaves behind can be easily recovered by anyone with the right software. A full format takes much longer but it does erase every byte of data. Select the "Enable File and Folder Compression" option if desired. Type a name for the volume and click "Next."
Click "Finish" after reviewing the settings that were applied to the new volume. If you want to change anything, click the "Back" button and format the drive again.
Select another drive or volume to format, or exit the Disk Management utility.