If you've been trying to update or restore your iPhone, iPad, or iPod touch, you might have encountered the iTunes error message saying that your iDevice could not be restored because an unknown error occurred (3194).
Getting error 3194 is most probably because you have been using TinyUmbrella, it has set your system's host file pointing to Cydia's SHSH caching server.
To fix iTunes error 3194, simply open TinyUmbrella, uncheck Set Hosts to Cydia on Exit in Advanced tab. Open iTunes and try upgrade again. The error message shouldn't appear anymore.