Conflicts with firewall
Elemental will completely freeze the entire computer if it is launched when a firewall that monitors outbound connections is up. ZoneAlarm is a firewall that does (and it's pretty popular, too) and normally when an unidentified program tries to access the internet from your machine, it pops up a little message saying "are you sure you want this program to access the internet." In most games, once you've tried to connect, you Alt-Tab, put the check mark in "don't ask again" and say "yes."
Elemental however hangs when waiting for a connection to go through. You cannot alt-tab. You cannot ctrl-alt-del, you cannot swap the focus, you cannot crash the program or issue any commands to it. You cannot send any commands to your computer. The *only* way to get Elemental to stop hanging is to actually unplug your computer. This is a pretty disasterous bug.
Steps to recreate
1) download and install Zone Alarm http://download.cnet.com/ZoneAlarm/3000-10435_4-10039884.html?part=dl-69168&subj=dl&tag=button
2) Try to run Elemental
I have only tested this on Windows XP, but I have tested it on four different computers. This actually also happens with Sins of a Solar Empire, but not with any other game I've played. ZoneAlarm comes by default on the PC I bought.
** Update **
* affects windows xp 32 bit
* does not affect windows 7 64 bit
* known to affect zone alarm installations
* known to affect comodo firewall installations
* Powering off your computer abruptly can cause hardware failure! Excercise caution, as I learned from experience