A globally unique identifier (GUID) is a unique reference number used as an identifier in computer software. The chance of 2 GUIDs being generated is highly unlikely, though not impossible. Source: https://en.wikipedia.org/wiki/Globally_unique_identifier #include <Array.au3> #include <StringConstants.au3> #include <WinAPICom.au3> Example() Func Example() Local $aArray[1000] For $i = 0 To UBound($aArray) - 1 $aArray[$i] = _WinAPI_CreateGUID() Next Local $hTimer = Time