I upgraded the site from 1.9.1 to 1.9.2 by using Magento Connect Manager.
I clicked the Check for Upgrades button, selected the update for each package, then clicked Commit Changes.
The upgrade processed from start (there are some conflict in the log) to the end (finished upgrading the last package) but never stopped. It kept running CHECK ....., then I clicked the Check for Upgrades button.
The problem occurs. Now no page is working except the error, The page isn't redirecting properly, on firefox.
I deleted all cache from var/cache/, but the problem is still there.
Any advice will be much appreciated!
Can you update your question with the errors whihc you are getting in console?
connect manager needs proper permissions and other web stack related issues can break it.
if you upgrading magento and you have separated your customizations, it is better just download magento 1.9.2 and overwrite everithing,