Safety-critical systems are often equipped with warning mechanisms to alert users regarding imminent system failures. However, they can suffer from false alarms, and affect users’ emotions and trust in the system negatively. While providing feedback could be an effective way to calibrate trust under such scenarios, the effects of feedback and warning reliability on users’ emotions, trust, and compliance behavior are not clear. This article investigates this by designing a 2 (feedback: present/absent) × 2 (warning reliability: high/low) × 4 (sessions) mixed design study where participants interacted with a simulated unmanned aerial vehicle (UAV) system to identify and neutralize enemy targets. Results indicated that feedback containing both correctness and affective components decreased users’ positive emotions and trust in the system, and increased loneliness and hostility (negative) emotions. Emotions were found to mediate the relationship between feedback and trust. Implications of our findings for designing feedback and calibration of trust are discussed in the paper.