When we click a link within a PDF file, it takes about 30 seconds to bring up the Allow or Block Security Warning dialog. We don't have this issue opening the same .pdf on an 9.4.x installation.
We've noticed this on domain-joined Windows XP with SP3 machines, and also vanilla Windows 7 machines that aren't part of the domain (and no other software installed). Both machines go through our ISA server, so I'm wondering if Reader is trying to go out to the internet to check something, being blocked and then timing out.
I've tested it with the local Windows firewall turned off and it hasn't made a difference.
What is Adobe Reader doing during this time, and more importantly, how can we speed up the time it takes to display the dialog?