Reattaching Drives on VMs Using Powershell (General access denied on vhdx)

I recently had some storage issues in the company lab which meant that after a lengthy CHKDSK that permission on all VHDX files was lost. The solution was luckily simple: Reattach each drive and the permission on the file was restored. Problem was then that there was more than 50 drives all in all. Solution then became, as it often is, do it with Powershell.

The script as follows (Download from Technet), formatted using https://tohtml.com/powershell/:

$States = ( [Microsoft.HyperV.PowerShell.VMState]::Off, 
            [Microsoft.HyperV.PowerShell.VMState]::OffCritical
          )

$VMs = Get-VM | ? {$_.State -in $States}
$DriveCount = ($VMs | Get-VMHardDiskDrive).Count
$Counter = 0

foreach($VM in $VMs)
{
    $Drives = $VM | Get-VMHardDiskDrive
    foreach($Drive in $Drives)
    {
        $Counter += 1
        # Some of these values (Path at least) disappear from the $Drive object when we remove it from the machine
        $ControllerNumber = $Drive.ControllerNumber
        $ControllerLocation = $Drive.ControllerLocation
        $Path = $Drive.Path
        $SupportPersistentReservations = $Drive.SupportPersistentReservations
        $ControllerType = $Drive.ControllerType

        Write-Progress  -Activity "Reattaching drives" `
                        -Status "Removing $Path from $($VM.Name)" `
                        -PercentComplete (100*$Counter/$DriveCount) 
        Remove-VMHardDiskDrive -VMHardDiskDrive $Drive
        
        if($SupportPersistentReservations)
        {
            # Shared vhdx
            Add-VMHardDiskDrive -VM $VM `
                                -ControllerNumber $ControllerNumber `
                                -ControllerLocation $ControllerLocation `
                                -Path $Path `
                                -ControllerType $ControllerType `
                                -SupportPersistentReservations
        }
        else
        {
                        Add-VMHardDiskDrive -VM $VM `
                                -ControllerNumber $ControllerNumber `
                                -ControllerLocation $ControllerLocation `
                                -Path $Path `
                                -ControllerType $ControllerType
        }
        
        Write-Progress  -Activity "Reattaching drives" `
                        -Status "Reattached $Path to $($VM.Name)" `
                        -PercentComplete (100*$Counter/$DriveCount)
    }
}