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 You can organize your alerts by selecting one of the following views from the Current View section of the Navigation Pane:

Active

 Organizes all your alerts that are currently active.

By Severity

 Organizes all your alerts by their severity.

By Server

 Organizes all your alerts by monitored SQL Server instance.

By Metric

 Organizes all your alerts by each of the metrics affected.

Agent Job Failures

 Lists all the alerts caused by Agent Job failures.

Blocked Processes

 Lists all the alerts caused by blocked processes.

Oldest Open Transactions

 Lists the oldest open transactions that have alerts associated with them.

Query Monitor

 Lists all the alerts associated with the Query Monitor.

Table Reorganization

 Lists all the alerts associated with table reorganization.

Custom

 Allows you to configure the view to show what is most important to you.

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You can also filter alerts based on the assigned tags.