I have my .msi installer that installs my custom extension and adds registry keys. So everything worked fine until 56.0.1 version, now Firefox shows me that I have no extensions installed, even though all files and registry keys are present. I tried reinstalling Firefox and my extension, but that didn't help. Then I took my Troubleshooting steps: 1. Installed my extension using my custom .msi installer 2. Downloaded and Installed my extension from Mozilla's Add-on store. 3. Extension worked. So maybe there is a changes to the registry installation method, or I am missing something?, because now I have to take two steps to get this thing to work.