How to Resolve Disk Formatting and Drive Letter Allocation Failures After a Disk Is Mounted to a Windows-based VM

Publication Date:  2015-01-26 Views:  504 Downloads:  2
Issue Description
After mounting a disk to a VM, a user attempts to format and allocate drive letters to the disk on the disk manager. However, the following error message is displayed.
Figure 1 Disk management error
Alarm Information
Handling Process
Solution 1: Resolve the problem by following the solution provided by Microsoft.
Link to the case:
Solution 2: Perform the operations shown in the following screenshot to resolve the problem manually.

Root Cause
1. View the device manager. The storage volume of the newly mounted disk is displayed as Unknown Device, but the storage controller driver functions normally. The possible cause is that the storage volume driver on Windows OS is loaded incorrectly.
2. View the case about the error on the Microsoft support website, uninstall the unknown device by following the provided solution, and restart the VM. The problem is resolved.
Link to the case:
The solution provided by Microsoft is as follows.

3. Create a logical volume and destroy the VM to simulate the unexpected power-off scenario. Sometimes the problem recurs and can be resolved by following the solution provided in step 2. The cause is that the logical volume is not written into the disk.