There are many related RAW drive problems and you may encounter such errors reported by Windows:
CHKDSK is not available for RAW drives. Drive is not formatted. Do you want to format it now?
RAW is not a regular file system type, usually the file system is FAT32, NTFS, NTFS5.
TestDisk is a portable data recovery tool. The tool was designed to help recover lost partitions and or make non bootable disks bootable again. TeskDisk is particularly useful when a system is not bootable because of a virus, software, or human error (accidentally deleting a Partition Table). This tool can fix a partition table, recover a deleted partition, rebuild or recover NTFS, FAT boot sectors, fix MFT, undelete and or copy files from NTFS, FAT, ext2, ext3 partitions.
Is it possible to recover RAW partition with TestDisk? The answer is YES.
How to recover RAW partition with TestDisk?
There are two places where store file system information: partition table (MBR) and volume boot sector (DBR). When the file system information provided on these 2 sectors of disk is not good you may see "The type of file system is RAW and CHKDSK is not available for RAW drives."
Ok. Try to mount this RAW drive as a slave inside the computer and then see if you can repair the partition table:
Unzip the downloaded TestDisk to your drive and open X:\testdisk-6.8\win > double click " testdisk_win" (the program doesn't have to installed).
1. At the first window select “No Log” and press the <Enter> key.
2. Select which drive to analyse, choose “Proceed” and <Enter>.
3. Select partition table type if it’s a PC.
4. Select “Analyse” then <Enter>. The drive/partition will be analysed.
5. Select “Proceed” at the next screen, then <Enter>.
6. Press “Y” if the partitions were created, “N” if not.
7. TestDisk should say “Structure OK”. Choose the drive/partition to fix. Then press <Enter>.
8. Select “Write” and press <Enter>.
9. Press “Y”.
10. Press <Enter> and close TestDisk. Reboot the computer.
TestDisk is a free and open source program, it can only fix basic RAW drive problems via command line. However, TestDisk doesn't provide easy-to-use and friendly UI, so it is hard to use for home users who don't have enough technical knowledge.
Luckily, there is a alternative tool: M3 RAW Drive Recovery. It provides easy-to-use and friendly UI to make RAW partition recovery very simple.
How to do RAW partition recovery with M3 RAW Drive Recovery
Step 1: Install and launch M3 RAW Drive Recovery. After that, select the RAW partition you want to recover.
Step 2: Click Next to scan the RAW partition you want to recover.
Step 3: After fixing RAW partition, please check the files in RAW partition before recovering.
Step 4: Click "Fix Drive" and do RAW partition recovery.