QPrinterInfo doesn't return network printers list when you have system right

When my service starts another application, which works with network printers, that app can see only local printers.
And when that app starts independently, it's all right. I found out that it is because of system privileges. And now I can't find out,
mayby it is a feature of the operating system, or bug.
I use a static function QPrinterInfo::availablePrinters(), which doesn't return network printers, when app starts with SYSTEM privileges.

Sorry for my English