So I'm working my way through the Staff of Magnus section of the College quest, and I beat the Dragon Priest, and took the staff. But the quest isn't progressing past "Find the Staff of Magnus". I looked up a walkthrough and discover there's supposed to be a NPC interaction after the fight...but it's not showing up.

Would returning to the College progress the quest as normal, or has something seriously borked?

Yes, the interaction is back at the College.

Is the NPC the ghost of Savos Aren? I don't think you have to talk to him, he just appears and says something then disappears.

No, according to UESP, I'm supposed to be accosted by a Thalmor agent.

EDIT: Returned to the College, I just keep getting a "What are you doing here, you need to get that staff!" remark, despite the fact I have the staff.

You are supposed to run into him on your way out of Labrythian,are you exiting through the shortcut door? You should be going up over the gated door and dropping down to a corridor where the ghost of Savos appears,continue on through there and after opening another door a Thalmor named "Estormo" confronts you.This is before you leave Labrythian to return to the college.

Yup. That Thalmor agent doesn't show up, nor does my quest journal update when I picked up the Staff of Magnus.

I suppose I may need to use the console to artificially advance the quest.

Yea, you may. If it's not updating after you grab the staff, I think the Thalmor agent will not show up. Without him, no one will acknowledge you back at the college.

Got it sorted out, though the next quest had a lot of issues attached to it as well (Though that could be due to the Immersive College mod I'm using). Had to disable the Eye's barrier effect just so the Psijics could take it away, and I had to...clean up...Maribelle. She wasn't hurting anything being hunched over by the pillar, but given her memorial outside it seemed in bad taste to leave her there.

I'm using that, too, and having trouble bringing the Staff back. The quest updated and the Thalmor Agent attacked me. I got to the college and helped "break through." Once inside, though, I can't affect Ancano nor the Eye. Tolfdir is not making his "suggestion", either. I'll do some tweaking, though, as I am liking this mod

Ah..good it wasn't just me.

I didn't know what was going on, so I just cheated my summonables in (Running Ordinator, which has a perk that increases range on summons, meaning I could port them into the shield proper) to wail on Ancano.

You'll have to open the console and disable the barrier. It's the only way to get the Psijics in position. Unfortunate, but like you said...it's a great mod. Have you found the teleportation orbs yet? Minute I found those, I knew I'd never be able to not use the mod (Use soul gems of various sizes - sizes vary depending on distance - to port to every major city and unlock a dias that can teleport you back for the same cost).

Well, the barrier is down. I just can't affect anything, ie: Ancano or The Eye.

Yea, I love the mod. I was scared to "touch" anything at first. Then found that much of it helps improve magical abilities. In the mornings, I have spent some time "learning" various magical skills with the instructors. (I hope that's from this mod...)

I do have a save from just before going from Winterhold to the College, so I'll reload that and see if things pan out better

I had an issue like that once, though it was due to Cutting Room Floor, and the College Guard it restores - though this was in an earlier version of the mod(before the Legendary patch version) - where he would enter the Hall and aggro Ancano too early, and thus everyone becomes hostile to Ancano and attacks him, too early. I had to disable the Guard in that case, so that didn't happen. Actually never enabled him after that, but I don't think that is a major problem.

And yep, gaining experience/levels in your magic skills while NPCs are practicing in the Hall Of The Elements is from ICOW.

Ooooh. I'm running Cutting Room Floor, so that might have been the issue.

Still, issues or no, ICOW is a great mod and despite the issues I had with the quest line, I don't regret it at all. Plus, being able to let Tolfdir be Arch-Mage is incredibly welcome...even if the Arch-Mage quarters in ICOW are incredibly tempting.

Funnily enough, I've been using Immersive College of Winterhold for some time, and just recently finished the quest there without problems. EDIT: And on multiple playthurus, too.

I don't run Cutting room floor, tho. Maybe that's the issue here?

Thanks for that! I am running Cutting Room Floor, also.