Using Diskpart in a PowerShell script won't allow script to reuse drive letter
- by Kyle
I built a script that mounts (attach) a VHD using Diskpart, cleans out some system files and then unmounts (detach) it. It uses a foreach loop and is suppose to clean multiple VHD using the same drive letter. However, after the 1st VHD it fails. I also noticed that when I try to manually attach a VHD with diskpart, diskpart succeeds, the Disk Manager shows the disk with the correct drive letter, but within the same PoSH instance I can not connect (set-location) to that drive. If I do a manual diskpart when I 1st open PoSH I can attach and detach all I want and I get the drive letter every time. Is there something I need to do to reset diskpart in the script? Here's a snippet of the script I'm using.
function Mount-VHD {
[CmdletBinding()]
param (
[Parameter(Position=0,Mandatory=$true,ValueFromPipeline=$false)]
[string]$Path,
[Parameter(Position=1,Mandatory=$false,ValueFromPipeline=$false)]
[string]$DL,
[string]$DiskpartScript = "$env:SystemDrive\DiskpartScript.txt",
[switch]$Rescan
)
begin {
function InvokeDiskpart {
Diskpart.exe /s $DiskpartScript
}
## Validate Operating System Version ##
if (Get-WmiObject win32_OperatingSystem -Filter "Version < '6.1'") {throw "The script operation requires at least Windows 7 or Windows Server 2008 R2."}
}
process{
## Diskpart Script Content ## Here-String statement purposefully not indented ##
@"
$(if ($Rescan) {'Rescan'})
Select VDisk File="$Path" `nAttach VDisk
Exit
"@ | Out-File -FilePath $DiskpartScript -Encoding ASCII -Force
InvokeDiskpart
Start-Sleep -Seconds 3
@"
Select VDisk File="$Path"`nSelect partition 1 `nAssign Letter="$DL"
Exit
"@ | Out-File -FilePath $DiskpartScript -Encoding ASCII -Force
InvokeDiskpart
}
end {
Remove-Item -Path $DiskpartScript -Force ; ""
Write-Host "The VHD ""$Path"" has been successfully mounted." ; ""
}
}
function Dismount-VHD {
[CmdletBinding()]
param (
[Parameter(Position=0,Mandatory=$true,ValueFromPipeline=$false)]
[string]$Path,
[switch]$Remove,
[switch]$NoConfirm,
[string]$DiskpartScript = "$env:SystemDrive\DiskpartScript.txt",
[switch]$Rescan
)
begin {
function InvokeDiskpart {
Diskpart.exe /s $DiskpartScript
}
function RemoveVHD {
switch ($NoConfirm) {
$false {
## Prompt for confirmation to delete the VHD file ##
"" ; Write-Warning "Are you sure you want to delete the file ""$Path""?"
$Prompt = Read-Host "Type ""YES"" to continue or anything else to break"
if ($Prompt -ceq 'YES') {
Remove-Item -Path $Path -Force
"" ; Write-Host "VHD ""$Path"" deleted!" ; ""
} else {
"" ; Write-Host "Script terminated without deleting the VHD file." ; ""
}
}
$true {
## Confirmation prompt suppressed ##
Remove-Item -Path $Path -Force
"" ; Write-Host "VHD ""$Path"" deleted!" ; ""
}
}
}
## Validate Operating System Version ##
if (Get-WmiObject win32_OperatingSystem -Filter "Version < '6.1'") {throw "The script operation requires at least Windows 7 or Windows Server 2008 R2."}
}
process{
## DiskPart Script Content ## Here-String statement purposefully not indented ##
@"
$(if ($Rescan) {'Rescan'})
Select VDisk File="$Path"`nDetach VDisk
Exit
"@ | Out-File -FilePath $DiskpartScript -Encoding ASCII -Force
InvokeDiskpart
Start-Sleep -Seconds 10
}
end {
if ($Remove) {RemoveVHD}
Remove-Item -Path $DiskpartScript -Force ; ""
}
}
