I'm trying to change the flash drive's partition style to GPT using PowerShell, but the cmdlet throws "The disk has already been initialized" (even though I've cleaned the drive):

PS C:\WINDOWS\system32> Clear-Disk 5 -RemoveData -RemoveOEM

PS C:\WINDOWS\system32> Get-Disk 5

Number Friendly Name                            OperationalStatus                          Total Size Partition Style          
------ -------------                            -----------------                          ---------- ---------------          
5      UFD 2.0 Silicon-Power16G USB Device      Online                                       15.14 GB MBR     

PS C:\WINDOWS\system32> Initialize-Disk 5 -PartitionStyle GPT
Initialize-Disk : The disk has already been initialized.
At line:1 char:1
+ Initialize-Disk 5 -PartitionStyle GPT
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (StorageWMI:ROOT/Microsoft/Windows/Storage/MSFT_Disk) [Initialize-Disk], CimException
    + FullyQualifiedErrorId : StorageWMI 41001,Initialize-Disk

How can I de-initialize the disk so that I can re-initialize it?

P.S. -PartitionStyle MBR shows the same error.

  • It looks like the Clear-Disk cmdlet is not working as it should or the drive is not properly clearing the data as the drive should revert back to a partition style of RAW after it is run. Do you have this issue with other storage as well? Feb 27, 2017 at 22:45
  • I see this with two different models of USB drives as well. If I try the diskpart equivalent (select disk and then clean), the drive becomes MBR instead. Wondering if USB drives can't be raw... Dec 14, 2017 at 20:39
  • 1
    I was running into the same issue. I searched and found this Microsoft Doc that states, "You cannot use the GPT partition style on removable media."
    – Paul Mayle
    Dec 29, 2018 at 17:31

2 Answers 2


Clear-Disk does not uninitialize removable media, only disks (HDD, SSD, VHD, etc.). To change the partition style of a removable medium, you can use Set-Disk with the -PartitionStyle parameter:

Set-Disk -Number 5 -PartitionStyle MBR

To view an example on how you can use Set-Disk inside a pipeline, you can have a look at my question on SO.


When you want to start over, start with a RESET. Then you can initialize, format, and perform other operations. Remember to put the disk in maintenance mode if it is in a cluster.

  • What do you mean with RESET? How to perform a reset using PowerShell?
    – SuperJMN
    Jul 3, 2020 at 18:55

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