When one travels the "Fallout 4" wasteland it becomes clear at an early stage that companions will indeed become handy, necessary and sometimes invaluable to the game. It also becomes painfully obvious that your companions don't always behave just exactly as you'd desire and they might temporarily, for reasons unknown, become lost. This occurs sometimes because of a software glitch or sometimes it's user error. Either way, the frustration of wondering where your companion went is a sinking feeling that anyone who has logged enough hours into this Bethesda masterpiece has experienced.
Never fear, there are some easy solutions to your problem and we'll discuss your options should you find yourself mysteriously alone in the game.
Unlocking the various "Fallout 4" companions
In total, 13 companions are available inside the standard version of "Fallout 4" that you can have accompany you including Cait, Valentine, Piper, Dogmeat, MacCready, Curie, Preston, Codsworth, Paladan Danse, John Hancock, Strong, Deacon and X6-88. At any given moment you may by accident dismiss them, which I have found to be one of the main causes of companions to become lost. Most likely in this scenario your companion will most likely be located at the preferred settlement you most often use, probably Sanctuary, the main area of operations in the video game.
Save often to negate future frustration
As a word of advice, save often so that in the last resort you can revert to your last saved game when you know your companion was safe and sound. Otherwise, fast travel to the settlements you most often visit and look around for your lost friend. Sometimes this method is the last ditch effort to locate your lost pal, but it can be the fastest solution to your problem.
It's too bad that Bethesda didn't have enough foresight to include a console menu option to find your companions or summon them on demand. It's an excellent option to possibly include in future versions of the franchise.
Settlement bells can offer hope
Companions and settlers respond well to the settlement bell option. In your settlement open up the workshop menu and then select Resources.
Next, pick Miscellaneous and in that category you will locate the bell. Hopefully you have four wood and four steel and, if those resources are available, construct a bell in the most central spot your settlement offers. Hit the bell, ringing it loud so all the settlers and your companion may here it. If you've done the procedure correctly it should be a rally point at which everyone in your town gathers. Hopefully your lost companion is among those that show up!