LastPass Disabled on Firefox 43.0 Update

UPDATE 16/12/15 @ 10am: LastPass has signed with Firefox and its plug-in official available on Firefox plugins store. Learn more from LastPass’s blog post

Are you LastPass user on Firefox like me? Most probably you may came across the problem of not able to use LastPass plugin on Firefox right after Firefox 43.0 update. The reason is because Firefox has introduced plugin signing as part of Firefox security feature, to sign all plugins with developers.

Unfortunately, it seems like LastPass has not submit the signing with Firefox yet, hence you will find below error showing that LastPass plugin is disabled on Firefox update 43.


The only solution for time being is disable the signing check on the plugin. Here are the steps to disable plugin signature checking.

  1. Open up about:config on your browser (typing on the URL address bar)
  2. Search for “xpinstall”


3. on “xpInstall.signatures.required”, double click it change it from true to false.


Last but not least, restart your Firefox browser, and LastPass plugin should come back on Firefox browser.

Until then, we have to wait for LastPass to sign the plugin with Firefox to enable the check again.