I just want to throw this out right now, there might be a perceived spoiler in this, but a super minor one regarding a companion...

I have been using Arcade as my companion, when I was running he and rex were with me. Then, I entered a different room, the game loaded, and rex was with me, but Arcade was not. HOW DO IT GET HIM BACK? I went outside, he wasn't there. I went back to Fort Mormon, he wasn't there. I have a saved gave where he was with me last, but it is like 3 hours before and I have no interest in going back to then, unless I absolutely have to. I am using the PS3 version. Any and all help would be wonderful!

Thanks in advance.

I had the same problem with Boone. He disappeared but I couldn't recruit anyone else because he was still attached to me.
About 6 hours of playing later I fast traveled to the strip's north gate and he popped out of nowhere.
Try to recruit another human companion. If you can't then you're just going to have to be patient hope he magically appears again.

I have also lost Boone now, can't recruit anyone else either. Any dev who can say if this is in progress of being fixed? Or maybe some hint on how to get him back?

Have had this issue with Boone no less than 5 unique times. Twice at the Strip, the rest in random spots (one I can recall at Jacobstown).

He was there one second, then gone when I'd load into a new area. He'd be gone for long periods of time before randomly showing up again on a subsequent rezone. For example, the time he vanished at Jacobstown, he magically showed up hours later when I zoned into Freeside North after I had done several side quests without him.

I don't think there is a way to get them back once they go missing like this short of reloading an autosave or an earlier save.

While I can't guarantee this will work, you could reset Arcade by obtaining another companion and then returning to his original P.O.I, Fort Mormon is it?

Reno