Symptoms
- Disk Management shows the drive as 'Unknown' and 'Not Initialized'
- Drive doesn't appear in File Explorer at all
- Drive is new, just installed, or was recently used on another system
- Drive previously worked and had data on it
Likely causes
- CommonBrand-new drive that has never been set upNew internal and some external drives ship without a partition table.
- PossiblePartition table corrupted or wipedThis can happen from a bad shutdown, malware, or drive errors.
- PossibleDrive was previously used with a different partition style (MBR vs GPT) that Windows can't reconcileSwitching systems or drive enclosures can trigger this.
- Less commonFailing drive electronics unable to report a valid tableMore serious hardware failure can also produce this exact message.
What to do
- If this is a brand-new, empty drive, right-click it in Disk Management and choose 'Initialize Disk', then create a new volume; this is safe.
- If the drive previously had data, do not initialize it yet since that can make recovery harder.
- Try the drive in a different USB port or on a different computer to rule out a connection issue.
- Use data recovery software that can scan an uninitialized disk directly for existing files.
- Once any recoverable data is copied elsewhere, initialize and format the drive for reuse.
- If recovery software can't read the drive's data area at all, the drive electronics may have failed.
Tools and parts
- Data recovery software that supports raw disk scanning
When to call a pro
If this was a drive with important existing data, don't initialize it yourself; get a data recovery professional to attempt a raw scan first.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.