That guard. Will NOT. Go. AWAY. I sneak, he sees me. I wait until his back is turned, he turns right around and tells me for the umpteenth time that I'm trespassing here, and better get out.

So I wait until the Jarl's uncle goes to bed, follow him into the room. At first I think I've got it sorted, he starts talking to me, rants about Ulfric. Right about the point where I'm going to ask him for help, the guard goes hostile and attacks Jenassa! RRGH!

.....what?

The Compelling Tribute Quest? In the Civil War? Where you have to get into the old man's room to find the evidence that he's a worshipper of Talos.

dafuq did i just read? You could mention the quest and give us a more umm understandable situation...

I did mention the quest. Compelling Tribute. That's what it's called.

are you on pc or console?

I don't think that quest is actually part of the Civil War questline...
Do what I did: Drop-pocket a fury + damage health potion in the Justicar's inventory and let the guards kill him.

its on the stormcloak side of the civil war questline. you have to blackmail the markarth steward.

Oh, okay. I haven't gotten that far yet. There's a side quest where the Thalmor ask you to find a unique amulet as well... http://www.uesp.net/wiki/Skyrim:Search_and_Seizure

So much paranoia in Markarth....

Yeah i remember the Thalmor one.

Heaps of people seem to have issues with Markarth.

I'm on PC, and a youtube video helped me figure it out. (Tell my follower to wait, and then be Veeeeeeeeeeery patient with the sneaking.)

I just watched the guard's routine and snuck up to the door as quickly as possible when he went around the corner. Pretty sure he came back down and saw me but I was in the old man's room and closed the door behind me before he could say anything. Once the door was closed, the guard couldn't see me so I might as well not have been there at all as far as he was concerned. After talking to the old man I just walked out, the guard was right there and gave the usual bit about "you don't belong here" and I just walked away and picked up my follower and got the hell out of Dodge. They don't go hostile if you just move on, the only tricky part was waiting until I had time to get all the way to the steward's door without the guard getting a chance to interrupt me while he was standing right in my way. The really scary part was that I couldn't remember exactly which room it was at first and wandered into the Thalmor's quarters on the first try... a real case of "hello I must be going" because I'm pretty sure they had death squads after me by that point and they were NOT happy to see me.

It was easier on my first playthrough, I'd already become Thane of Markarth before I started the CW stuff so I don't think anyone had any issues with me wandering around Understone Keep.

The only reason you take a follower anywhere you need to sneak is so you can fail at sneaking.

There might be a sneaky follower in this game, but I have yet to find one that does not mess things up for me at some point.

It sounds like a bug.

Theres one in dragonsreach were the jarls children repeadly say go away, when you are nowere near them.
The other characters do too.
You're meant to be there, but they get stuck repeating a nonsensical line.

Theres also a pain in the ass bug were characters talk to you if you so much as breath near them. I spent 3 freaking days trying to pickpocket Heimskr for the hideous Tg trophies and quests, and he would spin on the spot and talk to me constantly.
Eventually the idiot went to his house, and just as he was going in he turned and talked to me. I was like, just go to freaking bed you stupid man!

His level of perception does'nt sound right. He's easier than that to get past.

You could make yourself as invisable as possible and run when his back is turned.
Or go away and hope it resets.

Going in without any followers will help a lot. They're useless at sneaking.