Virtual reality (VR) technologies are increasingly marketed to knowledge workers as productivity tools for focused, immersive work. Yet little empirical research examines the lived experience of sustained VR use for complex academic writing tasks. This study presents a 10-week diary study of a doctoral candidate using VR to compose her dissertation during summer 2025. Through weekly reflective entries, screen recordings, and artifact analysis, we examine the user experience dimensions of immersive academic writing. Our thematic analysis reveals six major findings: (1) technical infrastructure constraints dominated the writing experience; (2) embodied discomfort consistently limited sessions to 30–50 min; (3) affective dimensions shaped productivity; (4) learning curves remained steep throughout the study; (5) task type significantly influenced success, with structured administrative writing outperforming open-ended academic drafting; and (6) technical disruptions fragmented flow and made momentum recovery difficult. We argue that VR writing tools require task-appropriate design, realistic session expectations, and user agency to discontinue when needs are not met. These findings contribute user-centered evidence to technical communication scholarship on emerging composing technologies and offer practical guidance for graduate writing programs.