The basic or dynamic disk is not accessible and might have experienced hardware failure, corruption, or I/O errors. The disk's copy of the system's disk configuration database might be corrupted. An error icon appears on disks that display the Unreadable status.
Disks might also display the Unreadable status while they are spinning up or when Disk Management is rescanning all of the disks on the system. In some cases, an unreadable disk has failed and is not recoverable. For dynamic disks, the Unreadable status usually results from corruption or I/O errors on part of the disk, rather than failure of the entire disk.
Solution:
Using a command line
Open Command Prompt.
Type:
diskpart
At the DISKPART prompt, type:
rescan
Value Description
rescan Locates new disks that may have been added to the computer.
Notes
To open a command prompt, click Start, point to All Programs, point to Accessories, and then click Command Prompt.
You must be logged on as an administrator or a member of the Administrators group in order to complete this procedure. If your computer is connected to a network, network policy settings might also prevent you from completing this procedure.
Use Device Manager to scan your computer's hardware for changes. Then, use the DiskPart rescan command if your disk configuration has changed but the changes do not appear in Disk Management. For more information about Device Manager, click Related Topics.
When DiskPart rescans disks, it scans all attached disks for disk configuration changes. It also updates information on removable media, CD-ROM drives, basic volumes, file systems, and drive letters.
Rescanning disks can take several minutes, depending on the number of hardware devices installed.
Edit:
What choices do you have when you right click on it in Disk Manager.
