So earlier I got off my horse and went dungeon crawling. When I went back to look for my house he was gone. I tried to fast travel to a few places but my horse didn't follow me to the fast travel places. I checked the stables, but none of the horses there were listed as mine, although there was one at each stable that was not listed as stealing a horse. So I went to a new stable and bought a new horse, but still none of the horses are listed as belonging to me. I wouldn't worry about it so much, its just that whenever you get off a horse it wanders away. Anyone know a fix?

Update: So, using spawning codes I was able to spawn a bandit, ice wolf, and a chicken, but when I tried for the horse, nothing happened. Not sure what that means, but thought it would be relevant. Thanks in advance for your help!

Would actually like to help. I tried messing with the console once with horse ownership because I really wanted the spotted horse skin that they have at the Imperial camps but you can't seem to own one so I figured i'd go walk up and console flag it as player owned.

Apparently, for some reason, this flagged every horse in the world as owned by me (though I have no idea what that does for fast travelling and what horse spawns when I do because I was afraid to try it) since every horse I moused over now no longer was flagged as being stealable.

So anyway, I ended up fixing it by loading a previous save. I also found out that the bug triggered (for me) when I took the leap off of Bard's Leap Summit and talked to the ghost. Going back and not taking the leap fixed the bug. Hope this helps anyone else who had a problem!