If you've got a huge, open world Bethesda game, your very first order of business should be to find and download the unofficial fan patch. Like this one, it's guaranteed to fix hundreds of bugs, both major and minor, from small issues with items and dialog to big problems with quests and markers.
Best of all? The huge number of changes are designed to be as unobtrusive as possible, so they don't ever break other mods or become irrelevant with new patches. This is essential download material for Fallout 4 Game of the Year edition.