The SCOM default action account is the account that is used to gather information about and run responses on a managed computer.
Mostly the Local System is used as the Default Agent Action Account. This is recommended, unless a company has specific reasons why they can’t do this.
Local System is a low maintenance account on each agent that generally has local administrative rights to that operating system only.
Another alternative is to use a domain user account as the default agent action account, and this account should then be placed in the Local Administrators group on the operating system.*
In rare cases, the application being monitored does not allow Local System (or a local admin/domain user account) to have any, or enough rights to the application. When this happens, you need to use a RunAs account and profile.
*NOTE you need to use a domain user action account on your SCOM MANAGEMENT SERVERS that has local admin rights, this is known as the Management Server Action Account or MSAA for short
You can produce a csv file with the Action Account on each managed entity by running the following powershell command from an Operations Manager shell:-
Get-SCOMAgent | Select-Object DisplayName, ActionAccountIdentity, HealthState | export-csv c:\agentandmsaa.csv -notypeinformation
NOTE:-This powershell command is for SCOM 2012 only but can be amended to run on SCOM 2007.