I went inside the path (from Explorer inside Sandboxie) and then I got the same result ('SBIE2224 Sandboxed program has crashed: firefox.exe'). I use the PortableApps version of Firefox, & there the profile is under 'PortableAppsFirefoxPort ableData profile' For a normal installation it would probably be somewhere under 'UserAppData'. After that, navigate to the Sandboxed location where you installed it and launch it. With Windoze that would be similar, but Im not sure where the profile is, at least not for a standard Firefox installation. When the installation completes, close it (don't select Run Firefox.). Updates over 300 common apps check including portable apps Ability to cache updates for use on multiple machines No bloatware during installations. Install Firefox Portable directly in the Sandbox, ignore the autorecover prompts.

Said so, while Chrome works fine Firefox doesn't even starts. That starts after I updated Win10 and SB. I also have the problem with the 'UAC' that asks for the admin rights but I also have that problem when I launch the PortableApps interface or when I launch Chrome Portable.

Firefox portableapps