The Coronavirus pandemic has created significant challenges for higher education institutions and rushed them toward the utilization of IT resources to practice online learning as a replacement of the face-to-face classrooms. This study aims to assess the effectiveness of the online learning system (OLS) in driving student engagement and generating positive performance impact during the Coronavirus outbreak. A conceptual model is proposed by adopting the D&M model to examine the impact of the OLS overall quality dimensions (system quality, information quality, and service quality) on student's performance impact and to study the mediating effect of actual use, student satisfaction, and student engagement on this relationship. By depending on a sample of 781stuents at both ungraduated and postgraduate levels enrolled at public universities in Egypt, using a self-administrated online survey to collect the data and SEM-PLS to analyze the data. The results indicate the significance of OLS quality dimensions direct effect on actual use, student satisfaction, student engagement and performance impact. Also, student engagement has the highest direct effect on performance impact and indirectly it enhances the relationship between overall quality dimensions and performance impact. These findings suggest several theoretical and managerial implications which specifically highlight the importance of overall quality and student engagement as determinants of OLS effectiveness.