Powershell script to convert all xls documents to xlsx in a folder recursively

ConvertXLS.ps1

# XLS to XLSX Batch convert script
# Forked from https://gist.github.com/gabceb/954418 
# Works well using Office 365

$folderpath = "D:\XLS Files"
$filetype ="*xls"

Add-Type -AssemblyName Microsoft.Office.Interop.Excel

$xlFixedFormat = [Microsoft.Office.Interop.Excel.XlFileFormat]::xlWorkbookDefault
write-host $xlFixedFormat
$excel = New-Object -ComObject excel.application
$excel.visible = $true
Get-ChildItem -Path $folderpath -Include $filetype -recurse | 
ForEach-Object `
{
	$path = ($_.fullname).substring(0, ($_.FullName).lastindexOf("."))
	
	"Converting $path"
	$workbook = $excel.workbooks.open($_.fullname)

	$path += ".xlsx"
	$workbook.saveas($path, $xlFixedFormat)
	$workbook.close()
	
	$oldFolder = $path.substring(0, $path.lastIndexOf("\")) + "\old"
	
	write-host $oldFolder
	if(-not (test-path $oldFolder))
	{
		new-item $oldFolder -type directory
	}
	
	move-item $_.fullname $oldFolder	
}
$excel.Quit()
$excel = $null
[gc]::collect()
[gc]::WaitForPendingFinalizers()

Thank You so much for the script.

The powershell script converts to xlsx but it has a pop-up message (Message Attached)

How can I say Continue Saving as a Macro-Free workbook?

Thank You,
Madhuri Dara

Ignore my comment above. I could get past the pop-up by adding this:

$excel.DisplayAlerts = $False

-Madhuri Dara