Unfortunately I never did find a fix. The closest I ever got was by uninstalling the first content update (might want to try the others too) clearing the storage cache, then re-installing the content update(s) and starting the game again. This DOES NOT fix the issue with being unable to access the campaign and as I later found out any PvE content, but it does allow for some PvP to be played. Unfortunately over time the error seemed to be progressively more frequently concurring, meaning I got less and less play time before each Beagle error. I have since upgraded to Xbox One, which fixed the issue. I'm sorry for your inconvenience, Bungie totally abandoned/ignored us on this :/