By Emily / Last Updated September 9, 2019

My USB flash drive is changed into RAW!

“Several months ago, I bought a Patriot USB flash drive to store photos and videos of my little daughter. It works great all the time. But, yesterday, when I inserted it to my computer as usual, the Windows only showed an error message “disk is not formatted. Do you want to format it now?”. It was somehow in RAW file system and i can't access any files on it. What happened and why? Do you guys know any feasible USB RAW file system repair solutions? I don’t want lose any precious photos and videos. Thanks!”

Raw Drive Disk Management

Possible causes for USB being RAW format suddenly?

RAW file system is not a standard file system. That cannot be recognized by Windows operating system like FAT file system and NTFS file system. No matter the memory card, computer hard drive or other USB drives show RAW file system, you will be unable to access the data inside. As for the possible causes, apart from the virus/malware attack, power outage, unplugging USB without selecting "safely remove hardware and eject media" option, you should also consider the following factors:

>1. Bad Sectors

If the key area of the hard drive contains some bad sectors, the hard drive won’t work normally, and probably becomes raw file system.

>2. Partition Table Corruption

If the partition table of the drive is corrupted, the hard drive may also become raw drive.

>3. File System Structural Damage

If the file system suffers structural damage, hard disk partition may change into raw format.

Effective USB RAW file system repair solutions

Now comes the most important part: how to repair USB file system in Windows 10/8/7? Below are some effective solutions. In order to repair RAW USB without losing data, you had better recover the data from the raw USB first. Recoverit Pro is a reliable data recovery software you can try.

Solution 1. Check disk error

When it comes to checking whether there are some bad sectors on the raw USB drive, running CHKDSK probably is the first thing coming into your mind. But it is, in my experience, unreliable sometimes. For example, you might meet an error message: The type of the file system is RAW. CHKDSK is not available for RAW drives.

Therefore, you need a professional disk/partition manager. Here we highly recommended AOMEI Partition Assistant Standard. It can help you to check disk error in a few clicks instead of running complex commands. Windows 7/8/8.1/10/XP/Vista are supported. Next is how to check bad sectors on hard disk via this software in Windows 10.

Step 1. Download the freeware, install and run it to enter its main interface. Right click USB drive that shows raw and select Surface Test.

System Disk Test

Step 2. Tick on Quick Check and then Start.

Start Test System Disk

Solution 2. Repair damaged partition table

A partition table is a table maintained on disk by the OS describing the partitions on that disk. This term is most associated with the MBR partition table. If the MBR partition table is damaged or corrupt, then the hard drive might become RAW and the system will be unable to locate the partition to boot from and the boot process will be halted. To repair damaged or corrupted partition table, especially the MBR partition table, AOMEI Partition Assistant Standard can also help.

Step 1. Launch the freeware. Right click the RAW USB to select Rebuild MBR.

Rebuild System Disk MBR

Step 2. Choose a proper type of MBR for your current operating system and click OK.

Choose MBR Type

Step 3. Click Apply->Proceed to begin rebuilding the master boot record.


Solution 3. Recover the RAW USB to NTFS, FAT32, exFAT file system with formatting

If above methods do not make any difference, formatting it to a regular file system, like NTFS, FAT 32 or exFAT is a guaranteed USB RAW file system repair solution. More importantly, you can also use AOMEI Partition Assistant for this task. Below are the detailed steps of how to recover RAW disk to NTFS.

Step 1. Open AOMEI Partition Assistant. Right click the raw USB drive and select Format Partition from the menu.

Format Partition

Step 2. Choose NTFS from the File System tab and click OK.

File System

Step 3. Click Apply->Proceed to execute the pending operation.


As you can see, AOMEI Partition Assistant is a powerful software and provides several USB RAW file system repair ways, each one being easy to understand and follow, even for the computer newbies. Besides, if you upgrade it to AOMEI Partition Assistant Pro version to unlock more amazing features like recovering missing partitions, migrating only OS drive to SSD, allocating free space from one partition to another and more.

Bonus tips for avoiding hard disk to become RAW

Last but not least, we prepare some tips you can take a look at to avoid hard disk raw issue in future.

  • Don’t remove your disk from computers in an improper way. Always remember to choose “safely remove hardware and eject media” option.

  • Better to make a disk backup, which could help you recover the data easily when the disk suddenly turns into raw and then you can format it without any worries.

  • Never format too much of your hard disk.