''Digital Guardian is enterprise software that is only tested and compatible with Firefox ESR releases. Future versions of Digital Guardian will have a better error message about this incompatibility, instead of crashing. But since your computer requires this software, you will have to install the Firefox ESR version, or get it from your system administrator. '' Quoted from bsmedberg here: https://support.mozilla.org/en-US/questions/1001095#answer-585736