RAW file system is a state of the hard drive or other storage device which has no known Windows file system.
Because no file system exists on the drive, there can be no files or folders on the drive, and it cannot be used to store data.
The following error messages may appear
You need to format the disk in drive before you can use it.
Do you want to format it?
(When trying to open the drive in Windows Explorer)
The type of the file system is RAW.
CHKDSK is not available for RAW drives.
(When running CHKDSK)
This volume does not contain a recognized file system.
Please make sure that all required file system drivers are loaded and that the volume is not corrupted.
(During certain console operations)
The disk image isn't initialized, contains partitions that aren't recognizable, or contains volumes that haven't been
assigned drive letters. Please use the Disk Management snap-in to make sure that the disk, partitions, and volumes are
in a usable state.
Windows Explorer shows that both used and free spaces are 0 byte in size in the raw drive Properties. Also, no file system type is indicated.
The Disk Management shows the partition as either RAW or without a filesystem type, depending on the version of Windows in use.