Preflight droplet process returns too early – before it's done

Question

I'm calling an Acrobat preflight DROPLET from program that I'm writing, and I need to know when the files are ready, that is when the preflight fixups are done.
I need to know this in order to go on with some other file system stuff in my program, that needs to be done after the preflight fixups.
I guess the droplet just tells Acrobat what to do, and then exits. The Droplet process stays up for a while but exits before the work is done.
There is an question from 2009 asking the exact same thing, but no answer.  Preflight droplet returns too early
Since it's in a locked section of the forum I venture to ask the same question now, six years later.
Checking the modified dates of all files does not seem to work since a preflight obviously does not alter files that are not in need of being altered.
I'm on windows, and I don't know whether this is a platform dependent problem.
What should I do?
Thanks,
Andreas

Answer 1

This is not a good way to do it. But this is the way I do it now...
It seems to work but there is no guarantee that it will work in the future, or even on all machines.
private static int WaitForAcrobatReady() {
  // Get the current Acrobat instance.
  var app = new Acrobat.AcroApp();
  // While a preflight (droplet) is running, app.GetNumAVDocs() will
  // not return ANYTHING, it will just hang.
  return app.GetNumAVDocs();
To sum up the efforts of the last weeks: Acrobat doesn't seem to be made for inclusion in other automation jobs. This is just another thing that doesn't work.
(I had to use the C# library PDFSharp to do other things that Acrobat can do really well only that it's not possible to set those properties, or start that kind of actions, from "outside".)