I found a conflict between TI Connect (the tool from Texas Instrument to manage your calculator from a computer) and PDFCreator.
=> The first time you print a PDF (on any user session), it re-installs TI Connect silently !!!!!! and then it prompts the normal PDFCreator screen.
Strange, no ?
It doesn't matter the way / the order you install these apps. I've tried everything, the bug happen as soon as both apps are installed.
Since it happens only one time per user session, it is not really annoying. But for system admin who want to deploy such apps on a network, it is much more embarrassing.
This is a know bug from the Windows Installer. A wrong configured msi package can be the reason for such strange habit. MS deploys a tool called Windows Installer CleanUp Utility which can remove such software packages (not the application itselfs). -> support.microsoft.com/kb/290301
It works. The bug comes from the MSI (TI Connect and PDF Creator are both using it).
Well, now I'm tryign to use msiZap to remove TI Connect setup entries silently. I've tried a "msizap TPWA! {CA04376B-A6BA-F246-20B1-EBD703D8F0D2}" but it does not seem to work.