Anyone else who got this bug: when I completed the bloodbath quest one of the guards in Moonmoth Fort is attacking me on sight although Varro said he would take care of the bounty. So I'm basically on bounty 0 but one (always just one, not all) guard in Moonmoth courtyard tries to kill me on sight.

Replay the encounter without causing bounties? (taunt or frenzy them )

I guess I'll have to restart a character coz' after I killed a few attacking guards ( in god mode) I went to other quests and overwrote all the previous savegames :verymad:

You don't have to restart your character. I know there's a solution to this, I've used it. I can't remember it right now so I'll go find it and edit it into this post.

EDIT: I can't find it, but I'm fairly sure I managed to stop them attacking by managing to talk to an imperial guard while invisible (the guy on the bridge between Sadrith Mora and Wolverine Hall is good, he's alone) while I had a small bounty, then while you talk he asks you to pay the small bounty and from then on they stop bothering you. It has to be one of the ones that'd normally be attacking you that you need to talk to, and I suspect you'll have to do it for every type of guard that attacks you on sight but it sounds like you only have Imperial ones to worry about. If I remembered wrong and this didn't work for you then the only other solutions are to use the console, so if you're an XBox player and the first idea doesn't work you're stuck.

Thanks for the help. I deleted the saves and started a new one but if I get into the same bug I'll apply your hint thank you.

Question...on your other save with the guard attacking, when you went back to Varro, how did you get to him? Did you set a Mark right in front of him before heading to the club to kill the "bad people"? Did you just use Divine Intervention and it put you in the courtyard of Moonmoth? Or did you just run back to Moonmoth?

If you answer no to option 1 and used either option 2 or 3 then that is probably what caused the guard to attack you all the time. Unless you taunt the "bad people" into attacking first as some suggest. You will get a Death Warrant. So any guard that sees you before you reach Varro will attack on site. Even though Varro removes any bounty and death warrant, that one guard (or any others that might have spotted you) never seems to get the memo.

I ran back to Moonmoth, the guards attacked me but I didn't fight back, I just managed to go inside and finish the quest. When I went out of the building with bounty 0, only one of the guards attacked. I was too low level so I tried to escape but the damn Imperial was too fast and all the healing potions didn't get me far. So the only option was to enable God mode and kill him outside the fort. I thought that would be it, because the other 2 or 3 guards in the fort didn't attack. Then I did other quests (I don't remember if I met other guards though so I don't know if the issue was only in Moonmoth) and when I came back to the fort the scenario repeated, only one of the guards attacks on sight. I thought it was the same one, I thought he respawned somehow, but no, all the wares of the first one were where I left them in the road.
I didn't lose so much, I only had 7-8 hours into the game but I learned 2 things: make more savegames (I had only 4 or 5 that I kept overwriting) and I'll taunt the "bad people" until they attack.

i am not sure what is going on with you. when i do the quest, i set a mark near the guard officer that gives the quest. after doing the bloodbath to get rid of the bad guys, then recall to the quest giving guard. go invisible when i get near the fort. the outside guards don't follow me into the fort.