I use the manor in Balmora for my house so I'm going to and from all the time but lately the dunmer at the silt rider appears to have disappeared so I can't actually get the silt rider from Balmora now. The silt rider is still there though, just not the guy I had to speak to to travel.
I had a look around the place in case he fell off the platform but there's no sign of him.

Any ideas?

If you're on PC, you can use the console to bring him back. Walk to the silt strider platform. Open the console with the button that's under Esc (usually tilde, as in ~ button). First, you can try writing

ResetActors

. Then press enter. This code puts all the NPCs back to their starting positions, so that if the guy is alive somewhere, he will teleport back to the platform. If this doesn't do anything, it's a sign the guy has just, well, vanished from the world. In that case, you can try for example

PlaceAtPC, "selvil sareloth", 1, 1, 1

. After pressing enter, the guy should appear in front of you.

Now, if you aren't playing on PC, there's no way to bring him back, and I've wasted my time giving you the console codes.

Sorry. Should have said that yes I am on a PC.
Wouldn't have asked otherwise as I semi-guessed that console magic (governing attribute intelligence?) would be required.

"ResetActors" did the trick but when I went back, he was gone again. However, this time he had just fallen off the platform and I was still able to talk to him and travel.

Thanks a bunch.

What a clumsy oaf.

The one in Gnisis is just as bad, or worse. And it's an even bigger drop off that platform. They must issue slowfall spells to all the caravaners...

uncle festering, I got a big laugh a couple of months ago when I discovered that the same guy had fallen off the platform too. I had to use a Command Humanoid spell to move him back into place. This is the first time I've played this game and I'm having a ball. I just figured that physics was different in Vvardenfell.

It's a perennial problem with him. I really don't know why they didn't make him stationary. He seems to have a real problem with balance, and it's a wonder he doesn't injure himself considering the heights from which he falls.

I had the same problem with him a few months ago. He didn't just fall off, he completely disappeared. I later found him at the silt strider port in Vivec.

Ironically, he is stationary. Morrowind has this odd bug where every time you enter an area, all of the NPCs shift just slightly to one side.

Yup.

I guess that sometimes the guy can drop inside the platform instead of off it. That's why maybe he seemed vanished. He wasn't, he was likely just stuck inside the platform, as many games especially from this era had people stuck into walls, etc.

Maybe he got designated to a new assignment.

So you're saying it's just a jump to the left, and then a step to the right...?

(From an obscure text entitled the Rocky Horror Picture Morrowind Show.)