Perhaps the process you are starting is contrubuting to this, by doing it's
own forwarding and threading...

Anyways, one approach would be to stitch the pdfs into one before printing
(the first google I found was PDFtoolkit (by gnostice), but bound to be
others) - but this might take a lot of space / memory. Also perhaps look at
what is actually doing the printing; is this your code? Perhaps another
product might offer synchronous printing? (looks like PDFtoolkit also does
printing - no idea whether it is any good)

That's my £0.02, anyways,

Marc

Wait for process exit on each process at the bottom of the loop.  It is
using multi-threading as your using multiple processes - so the last
document you start could be finished before the first document.