There are two types of alerts in System Center Advisor: auto-closing alerts and non-auto closing alerts.
An auto-closing alert is generated when Advisor detects the status of a certain event or condition, such as a configuration parameter or missing update. When the condition is addressed Advisor automatically closes the alert. You can also close it manually if you determine the situation is resolved.
A non-auto closing alert is generated when Advisor detects an event that occurs at a specific point in time. This type of alert cannot be auto-resolved by Advisor, but you can close it manually.