Your crash is linked to a recent bug report (bug 1291738) about crash on startup when Websense Endpoint is installed.

Do you have this application? If yes, maybe try to ask support on Websense support, maybe they ahve already an hotfix ofr FF48.

There are some Websense versions before 8.1 which are causing startup crashes on Firefox 48 and 49. Websense is suggesting that affected users should update to the latest version of their software, or ask their IT admin to update across their organization. This document from Forcepoint outlines their supported versions for each browser: https://support.forcepoint.com/KBArticle?id=TRITON-AP-ENDPOINT-Browser-Certified-Product-Matrix