Symptoms
- 'The disk is write-protected' message when copying files
- Physical lock switch present on the drive's side
- Can read files but can't delete, rename, or add new ones
- Message appears on every computer the drive is tried on
Likely causes
- CommonPhysical write-protect switch is enabledSome SD cards and USB drives have a small lock switch that's easy to bump.
- CommonRead-only attribute or disk flag set in softwareWindows can mark a whole drive read-only after certain errors.
- PossibleDrive is nearly full and misreporting as protectedSome drives throw this error when they run out of usable space.
- PossibleFailing flash memory defaulting to read-only for safetySome drives lock themselves read-only once they detect wear.
What to do
- Check the side of the drive or SD card adapter for a physical lock switch and slide it to unlocked.
- Open Command Prompt as administrator, run 'diskpart', select the disk, and run 'attributes disk clear readonly'.
- Check available free space in case the drive is reporting protection due to being full.
- Try the drive on a different computer to see if the lock follows the drive or is specific to one PC.
- If the drive was flagged read-only after errors, back up its data since this can signal early failure.
- If nothing clears the protection and the drive shows other errors too, treat it as failing and replace it.
Tools and parts
- Access to Command Prompt or Terminal
When to call a pro
If clearing the flag fails and the drive is old, back up what you can and retire it rather than fighting a hardware fault.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.