I've lost track of the default values for these two settings (which may change at any time anyway) but regardless of the current default, these settings should be verified periodically.
Another annoyance comes into play when upgrading the Adobe Reader. It often (always?) requires Windows to be re-booted. What's up with that? Millions of Windows programs can update themselves without requiring the system to restart itself.
From a Defensive Computing perspective, I don't want applications making the types of changes to the operating system that necessitate a reboot. Not only is the reboot inconvenient, mucking around in the OS is an accident waiting to happen. Heck, I prefer portable applications specifically because they go out of their way to avoid impacting the system.
One change the Adobe Reader makes to the system is adding new programs that run automatically at startup time. This too, is poor Defensive Computing. I don't want anything to happen at system startup that doesn't absolutely have to happen. That is, I never want a problem with the Adobe Reader to get in the way of the computer booting up. One thing is important, one thing is not.
To that end, I've long been in the habit of disabling the Adobe Reader Speed Launcher (Reader_sl.exe). It's a knee jerk reaction for me at this point: update the Adobe Reader -> turn off the Speed Launcher.
Now, it's even worse. Recent versions of the Adobe Reader starting adding a second program to the list of auto-started applications, Adobe ARM (AdobeARM.exe).
So what's the safest PDF reader?
To me, it's the portable version of Sumatra.
Being portable, it makes no changes to the Operating System. It is also small and relatively feature-free. That is, there is less code and fewer features, making it safer by definition. The fact that you probably never heard of it, means few people use it, making it extremely unlikely that bad guys will target any bugs it may have.
If anyone sends you a PDF document, you are orders of magnitude safer opening it with the portable version of Sumatra.
If the PDF file, however, needs a feature that Sumatra does not implement, other PDF viewers include Foxit (available both normally installed and portable), Nitro and PDF-XChange Viewer.
Defensive Computing however, isn't everything. My main machine is configured to use Foxit by default, but the Adobe Reader is also installed. A couple times there were things that Foxit couldn't do, or do well, that were well handled by the Adobe Reader. If you need it you need it.
Why gripe about this now? When I updated the Adobe Reader today, I encountered yet another problem. More on that next time.