In at least the companions and the college of winterhold questlines I keep getting the same bug. Each time characters are having an interruptible dialogue (says this person is busy if trying to talk to them) after which theyre supposed to talk to me they dont do anything and I cant talk to them (says this person is busy). I've found that some people have had this bug as well but none of their fixes really work for me. I've tried bashing them or making them hostile but that doesnt always solve it and sometimes they wont accept my yield. Disabling and enabling or killing and resurrecting them moves the conversation onwards but skips large parts of it and it just gets stuck in the next phase. I've had to mainly move the quests onwards through console.

First time I had this when trying to join the companions and I had to get through the first quest with console. Now I'm stuck in trying to join the college of winterhold. Tolfdir is giving his first lesson but just gets stuck when hes supposed to ask for my opinion. I managed to get through that by killing and resurrecting him or making him hostile and yielding but then it just gets stuck in the place where hes supposed to cast a spell at my ward and I havent gotten past that. Does anyone have a fix?

I had this issue too back in 1.5. At the time, I was using a mod that autosaved the game for me at regular intervals. I'm guessing it probably saved at some important point and borked a script somewhere, causing all dialogue of that sort to be broken from that save onward. I since disabled it and started a new game, not having experienced the issue once since.

If you're using a mod like that, I'd recommend uninstalling it. If not, there's not much more I can tell you as I don't know why it happens either.

Not using anything like that. I dont suppose the vanilla game auto save stuff could cause this? I'm not an expert with scripts but I dont think that unless all conversations like this use the same script it wouldnt happen in every one of them.

While probably not as problematic as an autosave mod could be, I'm sure Skyrim's default save system could cause the issue. I'm more or less thinking of the "Save in Menu" feature, though I don't know if there are any exceptions as to when that's triggered.

I think the problem more or less stems from re-loading a save that was maybe more or less in the middle of running a script, essentially meaning the save was corrupt. What you could try doing is reloading the saves before your most recent save, and then going through a quest that initiates that sort of dialogue (such as the quest with Tolfdir) and see if it's triggered correctly or not. Hopefully, the save that still works isn't too far from your most recent save.

Again, don't take my word as fact on all of this, as I don't really know why this happens myself. I'm sure someone else will post in here knowing the exact reason and how to possibly avoid it.

Are you using patch 1.6 with USKP 1.0? Or 1.6 with any mod that edits vanilla dialogue?

I used to (used it for a very short time but didnt install it back when I had to reinstall the game and all mods and clean my save cause of other bugs) but I started the character with 1.5 and without uskp and tried to join the companions and got this bug. Also I hadnt touched any of my mods after installing them and starting a new game when trying to join the companions. I've had two other characters with many of the same mods (last was about six months ago though) and didnt run into this bug.