After having used Avast Internet Security for a while now, I have been growing more and more annoyed at how often Firefox would start up without a lot of plugin support. As searches through these forums have revealed very little help, I decided to look for myself what the issue is with a debugger.
It turns out my issue is caused by the fact that Avast's Sandbox tends to forward registry information that is seen from 64bit processes as opposed to what 32bit processes see - which is a problem for 32bit applications.
In my case, what this means is Firefox was attempting to read:
HKEY_LOCAL_MACHINE\SOFTWARE\MozillaPlugins
In an attempt to locate plugin information, Avast forwarded this on to Windows, reading directly from this same path in the registry - Which is an error for 32bit applications on a 64bit OS.
What should have happened, is that because this is a 32bit application, it's supposed to map:
HKEY_LOCAL_MACHINE\SOFTWARE\MozillaPlugins
to:
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\MozillaPlugins
The reason why Firefox can't find the plugins is because when it checks the registry, it gets the 64bit plugins result (which is obviously incompatible) instead of 32bit plugins.
Dirty work around for users wishing to work around this: Copy HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\MozillaPlugins keys to HKEY_LOCAL_MACHINE\SOFTWARE\MozillaPlugins
What is the best way for me to contact the Avast team to properly resolve this issue in the sandbox feature?