Run As profiles allow monitoring operations (monitors, rules, and tasks) to run as an account that has sufficient privileges ...

Run As profiles allow monitoring operations (monitors, rules, and tasks) to run as an account that has sufficient privileges to successfully monitor protected resources in the network. For example, you can use a Run As profile to read database properties or to log on to a mailbox. 
 
In addition, administrators can assign different Run As accounts to different monitored resources. This is useful when multiple resources are monitored by the same agent or management server, but each agent or server has a different security context. For example, a single SQL server might host multiple databases, but each database has a different owner.
 
Use this wizard to assign a Run As account that has the necessary privileges to the Run As profile.