This study aimed to investigate the impact of computer-mediated positive, corrective feedback via a learning management system called Showbie on Saudi students’ English writing in Riyadh. It also aimed to explore the written corrective feedback strategies that had a positive impact on the students’ English writing performance. Furthermore, the study also examined students’ attitudes towards receiving computer-mediated positive and corrective feedback when using Showbie as a medium. The sample of the study consisted of 24 EFL female students from the 5th level. The participants were divided into two groups: 12 participants in a control group and 12 participants in an experimental group. The data of the study were collected via two research instruments: (a) pre- and post- essay writing tests and (b) a questionnaire. The study yielded a number of major findings. First, the results showed that there were statistically significant differences between the performance of the experimental group and the control group on the post-writing test that showed the effectiveness of providing positive, written corrective feedback via Showbie on the students’ English writing. Moreover, the results of the study revealed that Saudi learners differed in their priorities of written corrective feedback strategies. The results showed that direct corrective feedback had a positive impact on their performance while indirect corrective feedback was the least prioritized written corrective feedback strategy. Furthermore, the results of the study showed that computer-mediated positive and corrective feedback via Showbie was useful. A number of pedagogical implications and recommendations were also discussed