How do I change a USB drive from read only?

Having a USB drive set to read only can be frustrating when you want to add or edit files. Luckily, changing a USB drive from read only to read/write is usually very simple. Here are some quick answers to common questions about making a read only USB drive writable again:

Why is my USB drive read only?

There are a few common reasons a USB drive may be set to read only:

  • The drive is physically locked – Many USB drives have a small switch on the side that can toggle between read/write and read only modes. If this switch is slid to the lock position, the drive will be read only.
  • The drive is formatted as read only – Drives formatted with write-protection enabled will be read only regardless of the physical lock switch position.
  • Drive errors – If the USB drive has experienced certain errors, the operating system may mount it as read only to prevent further damage.
  • Insufficient permissions – On Linux or macOS, you may not have permission to write to the drive if it is mounted with read only permissions.

How can I change the drive to read/write?

If your USB drive is physically locked, simply slide the small switch on the housing of the drive to the unlocked position. For other cases, try these steps:

  1. Safely eject the USB drive from your computer if it is currently plugged in.
  2. Inspect the drive for a physical lock switch and make sure it is not in the locked position.
  3. Plug the USB drive directly into your computer’s USB port. Avoid using a USB hub.
  4. Check the file system of the drive:
    • On Windows, open File Explorer, right click on the drive, and select Properties. Look at the File System type.
    • On macOS, select the drive and press Command-I to Get Info. Look at the Format field.
    • On Linux, open a terminal and run sudo fdisk -l. Check the System column for the drive.
  5. If the file system is FAT32 or exFAT, the drive can support read/write when unlocked. Skip to step 7.
  6. If the file system is NTFS, run chkdsk on the drive:
    • On Windows, open an elevated Command Prompt, type chkdsk X: /f (replace X with the drive letter), and press Enter.
    • On Linux, use sudo fsck.ntfs /dev/sdX (replace sdX with the drive path).
  7. Safely eject and reinsert the USB drive. It should now be writable.

How can I format the USB drive to be read/write?

If the drive remains read only, the last resort is to reformat the whole USB drive:

  1. Backup any important files on the USB drive. Reformatting will erase all data.
  2. On Windows:
    1. Open File Explorer and right click on the USB drive.
    2. Select Format from the menu.
    3. Choose FAT32 or exFAT as the file system.
    4. Check the Quick Format box and start the formatting process.
  3. On Mac:
    1. Open Disk Utility.
    2. Select the USB drive.
    3. Click Erase in the toolbar.
    4. Choose MS-DOS (FAT) as the format.
    5. Click Erase to reformat the drive.
  4. On Linux:
    1. Open a terminal and run sudo fdisk /dev/sdX (replace sdX with your drive path)
    2. Type p to print the partition table and confirm the correct drive.
    3. Type d to delete any existing partitions on the drive.
    4. Type n to create a new partition, then press Enter twice to accept the defaults.
    5. Type t to change the partition type, then type c to set to FAT32.
    6. Type w to write the partition table and exit fdisk.
    7. Format the drive: sudo mkfs.vfat /dev/sdX1

After reformatting, your USB drive should be reset as read/write.

How can I prevent the drive from becoming read only again?

To stop your USB drive switching to read only in the future, follow this advice:

  • Check for a physical lock switch and make sure it is never moved to the lock position when using the drive.
  • If formatting the drive, choose a file system designed for read/write like FAT32 rather than read only ones like ISO9660.
  • On Linux and macOS, unmount and remount the drive with read/write permissions if needed.
  • Use the eject option in your operating system before unplugging the USB drive.
  • If errors occur, fix them right away using chkdsk or fsck rather than continuing to use a damaged drive.

Why do I need the drive to be read/write?

There are several common reasons you may need to use a USB drive in read/write rather than read only mode:

  • Copying files to the drive – To add files to a read only USB drive, it must be switched to read/write mode.
  • Editing files – Existing files on the USB drive cannot be edited or changed if it is read only.
  • Deleting files – Files cannot be deleted from a read only drive.
  • Formatting – Reformatting a USB drive requires read/write access.
  • Installing OS – Installing a bootable operating system on a USB requires write permissions.
  • Writing logs – Some applications need to write logs or other data to external drives.

So in summary, anytime you need to modify, add, or remove files on a USB drive, it must be switched from read only to read/write mode first.

Can I recover data from a reformatted USB drive?

If you reformatted your USB drive without properly backing up all the data first, you may still be able to recover your files using data recovery software:

  • Stop using the drive immediately after reformatting to avoid overwriting data.
  • Try recovery software like Recuva or TestDisk to scan the drive and restore deleted files.
  • Some premium software like Disk Drill offer more powerful recovery features.
  • Recovering data is possible if nothing new was written to the reformatted drive.
  • The more you use the drive after reformatting, the lower your chance of file recovery.

So while data recovery from a reformatted USB drive is sometimes possible, it should not be relied upon. Always backup your files elsewhere before reformatting a USB drive.

Can I use a USB drive read only to protect against viruses?

Setting a USB drive to be read only can prevent any files from being written to it. This provides some protection against malware or viruses infecting the drive:

  • Viruses cannot copy themselves to a read only USB drive.
  • Malware or ransomware cannot encrypt files on a read only drive.
  • Without write access, the USB drive should be free from infection.
  • This is a simple way to guard against viruses from untrusted PCs.
  • The drive must still be scanned after each use to be 100% safe.

However, a read only USB drive has downsides as well:

  • You cannot add or edit files on the drive either.
  • Not all viruses are stopped – Human action may still cause infection.
  • You still risk infecting the computer you plug the USB drive into.

So while using a USB drive read only provides some protection from viruses, it is not a foolproof solution on its own. Practice safe computing habits too.

What are the risks of making my USB drive read/write again?

Changing a USB drive from read only to read/write carries minimal risks in most cases. But be aware of these potential issues:

  • Data loss if errors occur – Drives with errors risk more damage if forced to be writable.
  • Accidental lock switch – Sliding the physical lock switch back could lead to data loss.
  • Loss of access – If permissions or formatting is incorrect, the drive may become unusable.
  • Malware infection – Write access enables viruses or malware to infect the USB drive.
  • Physical damage – Forcing read/write may damage damaged drives further.

To avoid these risks:

  • Backup data before making any changes.
  • Carefully follow steps to enable write access.
  • Scan for and fix any errors using chkdsk or fsck.
  • Watch for the physical lock switch position.

Exercising caution and following procedures helps minimize any risks of enabling write access.


Changing a read only USB drive to allow writing again is usually a simple process, but does come with a small risk of data loss. Check for a physical lock switch, reformat in FAT32/exFAT, correct any errors, and be very careful when working with valuable data. With caution, you can successfully modify your USB drive to enable write access once more.