The latest release of Firefox, which would be Firefox 7.0, contained a bug that hid away some or even all add-ons of a user who updated a version of the browser to the latest stable iteration. Mozilla after noticing the problem stopped the distribution of automatic updates to users running the stable version of the browser on their computer.

The company was quick enough to provide a temporary solution for the bug that brought back all the add-ons for affected users.

Firefox 7.01, the update that fixed the hidden add-on issue is now available for all users. It can be downloaded from the official website or via the web browser’s internal updating. To do that one would have to click on Firefox > Help > About Firefox to trigger the check for a new version of the Internet browser (assuming that the one button Firefox menu is the preferred layout).

source:Mozilla Rushes Out Firefox 7.0.1 Update