Yesterday, i decided to upgrade my Firefox on my laptop from 6.0.2 into 7 via automatic updates, but it couldn't find any update at all. That's quite strange, since i updated the same browser on my workstation few hours earlier and it was fine.
Today, i got the answer from H-Online. It's said that Mozilla developers got a bug report that relates to add-ons being dissappeared after upgrading to Firefox 7, thus the developer decided to pause the automatic updates mechanism until this problem has been fixed in the next Firefox 7.0.1 release. They even release a new tool called Add-On Recovery tool as a temporary workaround for this problem.
Guess what? They have now released a new Firefox version with the fix incorporated, so if you have upgraded to Firefox 7.0, click on Help > About and you will see a new update that should upgrade your Firefox to 7.0.1