Ya know, I might just take a different approach. Now, I don't mean to offend anyone but this is what I'd do. 1. Pray about her and pray about the situation for about a week. Listen to what you hear/don't hear and act accordingly. 2. Ask for a coffee meeting, in the conference room, with the door closed between "Sandy", you and the boss. Make sure Boss knows to keep quiet. Boss should only be an observer. Boss should only intervene if someone pulls out claws. NEVER meet just you and Sandy because that is fraught with too many opportunities for "SHE SAID THIS TO ME." and there will be no way to defend if that's accurate. 3. Look Sandy in the face and say "Boss specified that you and I both be assigned to this project - as equals. I've done my very best at contributing valid work and I asked for the recognition in an outgoing email. (ie - that you and I are both listed as point persons). You didn't like that and then did your best to try to shut me out. Others have taken their clue from you and it's just not acceptable to me. Please tell me exactly what is blocking you from being fair to me. 4. Listen to what she says. Maybe she hasn't realized what a B she's been. Maybe she has stuff going on at home. 5. Thank her for her input and tell her you have no response at this moment. Tell her you'd like to think about it a bit and that you'll come back with a response in x time frame. 6. Write it all down, think about it, and propose a solution. "Sandy, I understand you didn't feel it necessary to have me involved in this project but Boss wanted me here. Now, you and I together, have to find a way to work together. Here's my plan: You can handle xyz and I'll do abc. Let's meet once a week to go over our individual progress and plan for the next week's activities. When we're done with this project let's ask Boss not to assign us to another project together and we can chalk this one up to a learning experience. Do you think this would work for us? Please let us know the resolution of what you do and how it all winds up.

Wow this sounds very frustrating and I’ve been in a similar situation before. I have to say I agree with Sophia’s comments above. You MUST have a conversation with your boss. In my particular situation I did not want to leave my position and wanted to just be on something/anything else because I felt like I wasn’t being heard. We were both wanting to take charge. Ultimately I took the initiative to see what other projects could use me and what new projects might be coming down the pipeline and asked for that by provided ideas and how I felt I could be useful.

Yikes. That is not a good situation, I'm sorry you have to deal with it. I think from what you said that your boss knows this is a problem (right?) and likely knew this would be a problem going in, but chose to do it anyway, potentially for a couple different reasons. One could be that there is a process going on with HR to remove Sandy, and this is proof they need to make it happen (in an ideal world), or he was hoping that you could make some headway with her where he couldn't (less ideal but unfortunately probably more likely). Or something else that I'm not thinking of but someone else might have an idea about. Either way, it's unfair for him to put you in this situation likely knowing that this issue would arise. Either way, it seems like you need to have a VERY frank conversation with your boss. If you are in a situation with this project where you feel like your contribution isn't meaning anything to the project, it's not good for you to be on it. It puts you in a vulnerable position with being able to show your value to the company. I don't think you want to give him an ultimatum, but saying something like "I am doing my best to contribute but it is clear that I'm no longer having an effect, how if I work on X project instead?" rather than asking your boss to do something about the situation is a stronger approach. And if he argues with you about it with some response like "Oh, no I'm sure you're doing fine" then I would stay firm. You can even ask him (not sure how close you are) something like: "Knowing how difficult Sandy is to work with, what outcome were you hoping for in this situation?" then double down on "Making a contribution to this company is very important to me, and it is just not possible with this current project structure." Hopefully some of this is helpful. Good luck!!

Thanks Jill - I hadn't thought of it that way, but definitely will. Like you said - disappointing, but better to be covered than caught by surprise!

Are you keeping track of what you are doing for the project? I'd keep detailed notes of your role for your own usage in case this comes up during review time or any other time in the future. It is disappointing to have to prepare to cover your ass but it's good to keep notes on what has been covered, what was said, and what was done or not done. That also helps you when you plan your own goals and self evaluation if that's part of your Performance Review.