There are a long list of stories about the issues with my PhD supervisor here in Academia.SE (see it here but these are not the only ones). So, I'm not going to repeat why I'm leaving my current research group. Last week, I decided to change my research group after almost 5 years. Despite its painful nature to switch after 5 years of work, I'm really hopeful that I can find a new PhD advisor who help me to finish my thesis and get my degree.
I was in the same situation of switching to a new research group in Fall 2019, but at that time, still I was not 100% confident that I will not be able to get my PhD degree with my current advisor. In fact, in Fall 2019, I left my current research group for a couple of months and searched for a new PhD advisor. The problem was that every time I reached to a professor, even in other departments, my current advisor sent an email to them and recommended them to not accept me as their student. At the end, when I realized that nobody wants to take me as his/her student, my current advisor requested to have a meeting with me and he said that we are in a really good shape in terms of research progress and I will be able to get graduated soon, which didn't happen at all.
Long story short, I reached the end of my capability to work with my current PhD advisor and even I don't want to see him or hear his voice again. I talked to our graduate coordinator in the department and he also said that I should change my research group and he supports my decision.
Tomorrow, I'm going to have a meeting with my current advisor as well as the chair of the department and graduate coordinator. Based on my discussion to our graduate coordinator, this meeting is going to be a formal briefing about what would happen when I switch to another research group. For example, who owns the data and intellectual property that are created during these 5 years, which I don't have any claim and I want to just accept their requests and do whatever they want me to do and just move on. My current concern is that my current advisor wants to repeat the same strategy to prevent other professors to take me as their student and after that again try to force me to back to his group, which even I prefer to switch to master degree but do not continue my PhD with him. I want to ask him politely tomorrow in front of chair of the department and graduate coordinator to stop sending email to prospective advisors that I would contact in the future, but I don't know how to do that. I really appreciate any help or suggestion.