Hi there

I was doing the ''deceiving the herd'' quest in windhelm, and before I killed the target I told Serana to wait for me so she would not attack the guards.
But when the guards caught me and after i payed my fine, she was gone. I cant find her any where in windhelm. I have tried waiting in white run for about 72 hours, maybe more, but she didnt show up.
Can I please get a console command to summon her?

thank you in advance

I do not know if this is your problem but for me she just disapears she is still there just you cant see her. I am not where you are in the game but just wander around the place you left her and see if her name shows up. I am trying to see if anyone else has this problem some times she will wander so it can be hard to find her.

At times I've lost her but she usually reappears when I enter a cave, doorway etc.

Yes that is the case with me also but it is not due to this invisibility issue( at least not all the time). It is due to the fact that she has a different build then older followers(I am just guessing here) she just can't travel the same paths as you for some reason so she may take a MUCH MUCH longer route then you took. But lets put that aside for now your issue is as you said "you asked her to wait". if she agreed willing to do so then she is still there and most likley invisible. it wont matter how many doors you go through or how many times you reload the save. If she stated that she would wait reluctintly then it is anyones guess where she is. I have used her through the intire Dawnguard Quest only doing some side quests along the way and have lost her for entire quests within the game. most of the time if she is invisible she will go through a "load door" and still be invisible. It is not by design it is a flaw in her matrix and can get quit annoying. I lets say, I have become accustome to her so I deal with it. Some times I will have to go all the way back to before she became invisible and start over. I am not sure if it is posible to do the entire Dawnguard quest without her so if you want to take the chance and hope she shows up at some time......well it is a risk you will have to take if you want her as a follower. One thing I do know for sure, if she is waiting for you, you will not be able to have any other followers. so if you can get another follower then it is posible you will be able to find her at the dawnguard castle that is if you joined them if not then I would guess she would be at her fathers castle. I would not go there if you are not a vampire. As far as console commands go I cant help you there, sorry