When you troubleshoot disks, you may encounter the loss of data disk partitions. This topic describes data disk partition loss in Windows and the solutions. This topic also describes the common mistakes and best practices for using disks to avoid the risk of data loss.


Background information

In a Windows instance, you can use one of the following tools to restore data on a data disk:
  • Disk Management: a tool provided by Windows for partitioning and formatting data disks.
  • Data restoration software: typically, commercial software. You can download the software from the official websites. The software is used for restoring data in file systems to which exceptions occur.

Status of the disk is Foreign and no partitions are displayed

In Disk Management of Windows, the disk is in the Foreign state and no partitions are displayed.


Right-click the space next to Foreign, select Import Foreign Disks, and click OK.

Status of the disk is Offline and no partitions are displayed

In Disk Management of Windows, the disk is in the Offline state and no partitions are displayed.


Right-click the space next to Offline, select Online, and then click OK.

No driver letter assigned

In Disk Management of Windows, you can find the information of the data disk, but no drive letter is assigned to the data disk.


Right-click the primary partition of the disk (such as Disk 1), select Change Drive Letter and Paths, and then follow the prompt to complete other operations.

Error occurred during storage enumeration

In Disk Management of Windows, you cannot view data disks. An error message similar to An error occurred during storage enumeration is reported in the system log.
Note The reported content may be An error occurred during enumeration of volumes based on your operating system version.


  1. Start Windows PowerShell.
  2. Run the winrm quickconfig command to restore data.
    When Make these changes [y/n]? is displayed, enter y to run the command.

After the restoration, you can find the data disk in Disk Management.

Data disk in the RAW format

In some cases, you may find that the data disk in Windows is in the RAW format.

If the file system of a disk is unrecognizable to Windows, the disk is displayed in the RAW format. Typically, this occurs when the partition table or boot sector that records the type or location of the file system is lost or damaged. The following common causes may lead to the loss or damage:
  • Safely remove hardware is not used when the external disk is disconnected.
  • Disk problems caused by power outages or unexpected shutdowns.
  • Hardware faults occur.
  • Underlying disk-related drivers or applications. For example, DiskProbe can be used to directly modify the disk table structure.
  • Computer viruses.

For information about how to restore data disks, visit Dskprobe Overview in the Microsoft documentation.

Windows also contains a large variety of free or commercial data restoration software to restore lost data. For example, you can use Disk Genius to scan and restore expected documents.

Common mistakes and best practices

Data is the core asset of users. A large number of users build websites and databases such as MySQL, MongoDB, and Redis on ECS instances. Data loss may cause huge risks to businesses. The following section describes the common mistakes and best practices in data security.

  • Common mistakes

    The underlying storage of Alibaba Cloud is based on triplicate technology. Therefore, some users consider that data loss will not occur in the operating system. This is a misunderstanding. The three copies of data stored in the underlying layer provide physical layer protection for data disks. However, if errors occur to the cloud disk logic in the system, such as infection with viruses, accidental data deletion, and file system damage, the data may still be lost. In this case, you must use technologies such as snapshots and geo-redundancy to ensure data security.

  • Best practices

    Data disk partition restoration and data restoration are the final solutions to data loss problems, but they may not restore data as expected. We recommend that you follow the best practices to create automatic or manual snapshots for data and run different backup schemes to maximize your data security.

    • Apply automatic snapshot policies

      Automatic snapshot policies are applied to system and data disks to create automatic snapshots for the disks. Note that after the system disk is replaced, the instance expires, or the disk is manually released, the corresponding automatic snapshots may be released.

      If you want automatic snapshots of a disk to be released along with the disk, you can select Delete Automatic Snapshots While Releasing Disk in the Modify Disk Property dialog box in the ECS console. If you want to retain the automatic snapshots, you can clear this option.

      For more information, see Snapshot FAQ and Delete automatic snapshots when releasing a disk.

    • Create manual snapshots
      Before you perform important or high-risk operations, you must manually create snapshots for disks. These operations include:
      • Update the kernel.
      • Upgrade or change applications.
      • Restore data on disks.

      Before you restore a disk, you must create a snapshot for the disk. After the snapshot is created, you can perform other operations.

    • OSS backup, offline backup, and geo-redundancy

      You can back up important data by using OSS backup, offline backup, or geo-redundancy.