There seem to be two threads with this same subject . . .
Actually, there are many threads on this subject :whistling: These just happen to be the latest. they won't be the last :spotted owl:
More often than not, everyone cries "bug" or reload or go to Vault 22. Most likely, you left him somewhere INSIDE. If ED-e is inside a building or room, he will show up on the World Map, but won't show up on the local map until you are also in the same interior location he is. Track him down with the World, then systematically search out all possible load rooms. Granted, it could be a bug . . . but probably isn't.
Good point.
Usually companions will open inside doors, and warp through access points when necessary. I just discovered a rather unique location though where a key card is required and, unlike most locations, the door closes behind you. If the companion isn't fast enough to walk through with you, they get locked out (or in, as the case may be.)