You should not clear an alert unless the condition that caused the alert has been rectified. When you clear an alert
The alert disappears from the alerts pane in which it was displayed.
The corresponding alerts icon changes to its normal appearance if there are no other unseen alerts of sufficient severity for that icon.
In a topology, the icon representing the system to which the alert applies returns to its normal appearance if there are no other unseen alerts for that system.
Any unexecuted alert policy actions defined for raising or acknowledging the alert are discarded.
Any alert policy actions defined for clearing the alert are initiated.
A message indicating that the alert was cleared is written to the log of the system to which the alert applies. Any text you enter when you clear the alert is also written to this log.
To clear an alert
In the alerts pane, right-click the alert you want to clear and click Clear from the shortcut menu that appears.
The Clear Alerts dialog box appears.
The Clear Alerts dialog box informs you that one alert will be cleared and allows you to enter optional comments. If you previously cleared another alert, any comments you entered at that time initially appear in the dialog box. Enter comments as desired.
Tip: It is recommended that your site develop a policy for the comments you enter. One possibility is to enter your initials and a description of the actions you took to resolve the problem. The information you supply is written to the appropriate logs.
Click OK to clear the alert. To avoid clearing the alert, click Cancel.
Alternative methods of clearing an alert include selecting the alert in the alerts pane, and then
Clicking Clear on the Edit menu.
Pressing the Delete key.
You can also clear multiple alerts at one time by selecting all of the desired alerts in the alerts pane and performing one of the above methods.