I think I've ran into a gamebreaking bug in DG. I was just exiting from the Soul Cairn with Serana in tow after having completed the quest to get the scroll from Valerica. I happened to have a quest from Serine to get a schematic and the quest location was the grotto just north of Solitude. I ran over there with Serana in tow and cleared out the hideout and got the plans. Upon leaving, I noticed Serana wasn't behind me, but I didn't think anything of it at the time, I just figured she would be with me when I fast traveled. However, she wasn't with me after that. At this point, I was a little paranoid, but I thought maybe she would just catch up with me at some later point or fast travel so I kept on going doing quests and other miscellaneous things.

I have since realized she isn't coming back, and since I was ready to talk to Dexion, I thought I'd back track to where I last saw here. Sure enough, I enter Blindwater Grotto and there she stands at the cave entrance. I talked to her and she still had the dialogue options like she was following me, so I left the cave to see if she would leave with me. No dice. I went back inside and told her we should part ways. She walked toward the entrance and disappeared, however, when I went to the entrance, the dialogue option to talk to Serana popped up and I ran into some invisible mass just in front of the exit. I thought it might have been a hiccup or something, so I walked around it and fast traveled back to Fort Dawnguard. No Serana. Worse, when I returned to Blindwater Grotto, she was standing there again. I told her to follow me and proceeded to try several different things before I just gave up.

Currently, I told her to wait there and I am going to run around and wait until I get the message that says your follower got tired of waiting and went home. If that doesn't work, I don't know what else I can do. Has anyone else had something like this happen? Is there a fix you used to get it to work or am I cooked? I recently restarted from a guy I put 90 hours into because I had some Dawnguard glitches, but it was nothing like this. I am on my 40th hour too, so I have put some time into this current guy. If I can't complete Dawnguard with this guy, I don't know. I don't think I have it in me to play through Skyrim anymore. I'm just really bummed about this. It seems like such a stupid glitch to encounter and in my previous playthroughs I never had any trouble with Serana just following me around.

I appreciate anyone who reads this and also any and all feedback, thanks!

From what I have read, and experienced, Serana is rather glitchy and has a tendency to get stuck in places doing nothing. She gets stuck in the life force drain when we are fighting together so I end up Fus Ro Dah'ing her to break her out of it. Maybe you could try that?

That was one of the things I tried. I thought I could Fus Ro Dah her out of the cave, but she didn't really do anything. I also tried turning her hostile and then running out and seeing if that would get her to follow, but it didn't work either.

Another question I have is: can you play through Dawnguard without Serana? It would stink not being able to, because she is an awesome part of the dlc, but if worse comes to worst, can I finish it without her? To me the answer would seem an obvious no, but I can't think if you really need her along for any quests past the Soul Cairn part.

I'm not sure, But Isran's dialogue consistantly includes Serana...Try call dragon or beast form to intice her to attack. If she does, run like hell and wait 24 game hours before meeting her back at Fort Dawnguard. I know that these bugs a ruining Vanillia, and if I'm dealing with permanent damage to my saves (like vampirism that CANT BE CURED), I wont have it in me to purchase another DLC. I hope bethesda is reading this....

Try this:
Go back to the grotto, DO NOT engage Serana in dialogue. Stand where she has line of sight, and see if she walks or runs toward you. (this may take a min so be patient) if she does then leave the cave, You should now have her back as a follower. If she does not, keep trying, something in the grotto has her stuck, and sometimes she works it out trying to catch you.

I spent an hour one with the same issue, and Serana finally unstuck herself and ran toward me. I've kept her close ever since.

If none of this works, your only option is a re-load, which svcks because of all the hours invested.

Good Luck, let us know if it worked.

What you wrote makes me depressed, because as soon as I entered the cave, she immediately behaved as though she were still following me, which I found to be extremely odd. I ran inside a little bit and she immediately followed me up the nearest ramp and started talking like nothing was off. That's when I ran right back outside and found out she was bugged.

If I can't find a fix for this, I am done for, because I rotate through a series of five saves and I saved over all the ones I had prior to entering Blindwater Grotto when I was out adventuring waiting for her to catch up. I have a few more tricks to try before I give in and sometimes stuff like this works itself out in the end anyhow. Regardless, this feels like a MAJOR mess up on Bethesda's part. I mean, your entire DLC revolves around a single NPC more or less and she is prone to bugs like this. Grrrrr.

It might be a silly answer to all this ^^ what you wrote but, try to hit her so she would go down on her knees. After she'd recover, she would normally follow you as if nothing happened at all.

^^ I got this problem as well in Volkhiar Castle and did the following and see there, she walked towards me again.

Cheers.