How to Fix the Disk is Read Only Error in Windows

Why does Windows Say the Disk is Read Only?

Windows shows The disk is write protected when it treats the drive as read only. You can open the files but you cannot copy, delete or format.

• A physical lock switch sits in the lock position.
• The disk carries a read only attribute.
• A registry value marks removable drives as protected.
• A BitLocker policy blocks drives that BitLocker does not protect.
• The file system has errors.

Heads Up. Copy the files to another drive before you try a fix. Some fixes end with a format.

How do You Check the Lock Switch?

Method #1: Lock Switch (Free)

Who it suits. Owners of an SD card, a card adapter or a USB drive with a slider. Extra application. None.

1. Remove the drive from the computer.
2. Slide the lock switch away from the lock position.
3. Reinsert the drive and copy a test file.

Clean the metal contacts with a dry cloth when the lock switch is not the cause. A broken lock switch on a card adapter blocks edits too.

How do You Clear the Read Only Attribute With DiskPart?

Method #2: DiskPart (Free)

Who it suits. Users whose disk carries a read only attribute. Extra application. Command Prompt.

1. Open Command Prompt as an administrator.
2. Type diskpart and press Enter.
3. Type list disk and note the number of the protected drive by its size.
4. Type select disk 2. Replace 2 with your disk number.
5. Type attributes disk clear readonly and press Enter.
6. Type exit and reconnect the drive.

Microsoft states on its attributes disk command page that you must select a disk first. The command clears the read only flag from that disk.

Check the disk number twice. The command acts on the disk you select.

The attribute sits on the disk and not on a single file. A set attribute makes the full disk read only.

Type attributes volume clear readonly after you select the volume when the disk shows no attribute.

Can the Registry Remove the Protection?

Method #3: Registry Value (Free)

Who it suits. Admins who accept a registry edit. Extra application. Registry Editor.

1. Press the Windows key and R together, type regedit and press Enter.
2. Open HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorageDevicePolicies.
3. Double click WriteProtect and set the value to 0.
4. Close Registry Editor and restart the computer.

The key is absent on many systems. Create the key and the value only when other methods fail. The steps appear on a Microsoft Q&A page for a read only USB drive.

Export the key before you edit it.

Does a BitLocker Policy Block the Drive?

Method #4: BitLocker Policy (Free)

Use it when. You own a work PC with Windows Pro. Extra application. Group Policy Editor.

The policy Deny write access to removable drives not protected by BitLocker mounts such drives as read only. Microsoft states the behavior on its BitLocker policy page.

1. Open the Local Group Policy Editor and go to Computer Configuration, then Administrative Templates.
2. Open Windows Components, BitLocker Drive Encryption and Removable Data Drives.
3. Open the policy and select Disabled or Not Configured.
4. Reconnect the drive.

A work PC can enforce the policy. Ask your admin before you alter it. Encrypt the drive with BitLocker when you must retain the policy.

How do You Fix File System Errors?

Method #5: CHKDSK (Free)

Use it when. Your drive shows errors or a RAW file system. Extra application. Command Prompt.

1. Open Command Prompt as an administrator.
2. Type chkdsk E: /f. Replace E with the drive letter.
3. Wait for the scan and plug the drive in again.

Try CHKDSK when DiskPart shows no attribute on the disk.

Format the drive only after you copy the files. A format erases the data. Read the guide for a pen drive that does not show on the computer when Windows fails to detect the drive.

Where Else do You Go From Here?

• Fix a drive that does not appear with the pen drive not showing guide.
• Open a protected document with the guide for a protected PDF.

Frequently Asked Questions

Author's Verdict

Check the lock switch and the DiskPart attribute first. Both take a minute and alter no data.

Use the registry and policy fixes only for a drive that stays locked and only with admin approval.

Key Takeaways

• A lock switch and a read only attribute cause most cases.
• Check the attribute before you edit the registry.
• DiskPart clears the attribute with one command.
• Copy the files before you format.

Related Guides

• Pen Drive Not Showing on Computer
• Protected PDF Cannot Be Used