Managing a growing WordPress community comes with many challenges. In some cases, it makes sense to monitor admin / user activity to identify suspicious patterns. User Activity Log for WordPress can help. It is a simple tool that helps you keep an eye on content updates, file uploads, plugin/theme activation and deactivation, and other activities.
The User Activity Log plugin keeps a record of important events happening on your site. Using this data, you are going to have an easier time figuring out what may be going wrong on your site. The script logs date, role, username, IP, action, activity type, and more. Want to get notified when a specific user logs on? No problem.
User Activity Log allows you to keep an eye on important events on your site and lets you customize its email notification settings. This is a free plugin.