Hi,
I am in my second year of Ph.D. I have been working on a project for almost one year. The project was to design a device. Although I have put in a lot of effort in manufacturing the device, I got stuck in the final stages. My supervisor suggested to either write up a masters thesis or change to a different supervisor. He has been very helpful and told me he will give good recommendation if I am going to apply for jobs using masters degree. But I talked with another professor who has agreed to take me as his student. But I am worried if I will be able to pass the PhD qualifying exam, which I have to finish in 5 months, using the work I will do under the new supervisor. I am most concerned about facing a situation in which I am left with no masters thesis after failing the QE. I will not be financially supported by the stipend once I fail the QE and will have to submit the masters thesis as soon as possible. I am not sure if I will be allowed to submit the thesis based on the work I have done under the old supervisor. I know this is not the right attitude to have while changing the supervisor, but I am worried about the worst case scenario. If I am making the decision to write the masters thesis now, I can at least be confident about submitting it in 3 months and get a recommendation from my current supervisor.

Please share your thoughts. Thanks in advance for helping me out making a decision.

I don't see why you can't go for the new project/supervisor, and then if things don't go to plan (if you don't manage to pass that exam), resort back to the idea of writing up what you've done as a Masters. Can you discuss this with the supervisors? They will understand that you need to have a back up plan.