Drives & data

Lost a partition on a drive

A missing partition usually still has recoverable data on the disk even though it disappeared from view, as long as nothing else has been written over it.

Difficulty
Moderate
Time
30–90 minutes
DIY cost
$0–$80
Pro cost
$150–$500

Symptoms

  • A drive that used to show two or more partitions now shows only one, or unallocated space
  • Partition disappeared after resizing another partition or using a partitioning tool
  • Disk Management shows unallocated space where a partition used to be
  • Data that was on that partition is now inaccessible

Likely causes

  • CommonAccidental deletion of the partition using a disk management toolIt's easy to select the wrong partition when resizing or managing disks.
  • PossiblePartition table corruption from a crash or improper shutdownThis can make an intact partition appear as unallocated space.
  • PossibleA partitioning operation (resize, merge) failed partway throughInterrupted operations can leave partitions in an inconsistent state.

What to do

  1. Stop making any further changes to the disk immediately to avoid overwriting the lost partition's data.
  2. Do not create a new partition or format the unallocated space yet.
  3. Use partition recovery software that can scan for and rebuild lost partition tables.
  4. Let the tool scan the full disk, which can take a while depending on size.
  5. If a partition is found, recover it in place or copy its contents to a different drive rather than the same disk.
  6. If no partition recovery tool finds anything, use general file recovery software on the unallocated space instead.

Tools and parts

  • Partition recovery software

When to call a pro

If partition recovery software can't rebuild the partition and the data is important, a data recovery professional has more advanced tools to reconstruct it.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.