@DougyDrumz Open the dialog without this information. Then in a separate thread (so you don't lock things up) get the info you need and populate the dialog once the info is available.
The way I would do that is just show a loading widget of some sort while it loads the info, then once loaded, show the real widgets on the dialog. You can use QStackedWidget to make this easy.
Another way is don't use dialogs. Modern applications rarely use them any more, except for things like File->Open.