The purpose of this research is to reveal the usability of virtual classroom application, which is used for synchronous lessons, in terms of effectiveness, efficiency, and satisfaction. A user-based approach was applied in order to collect quantitative data in this mixed method research. The effectiveness and efficiency of the system were revealed on the basis of 13 authentic tasks considering the status of the instructors performing the tasks, the number of critical mistakes they made during the tasks, and the time they spent on completing the tasks. The satisfaction of instructors with the virtual classroom application was determined through the SUS-satisfaction scale, observations during user tests, and interviews. A total of 12 instructors were in the data collection process. According to the findings, the completion rate of two of the seven tasks was over 90%. However, the successful completion rate of the total of six tasks was limited to 20%. It was also determined that the number of errors in the remaining 11 tasks exceeded the ideal number of operations and the completion periods were considerably longer. Overall results of the study revealed that the educator satisfaction levels for the Adobe Connect virtual classroom application were quite low.