Detail:  Using built-in accounts like Network Service or Local System as application pool or as service identities is not supported in a farm configuration.  The following services are currently running as built-in identities on one or more servers:

• SPTraceV4(Windows Service)
• SPSearch4(Windows Service)

Solution:  SPSearch4 will be assigned to run under a domain user with no additional priviledges.  This is done through Central Administration -> Manage Service Accounts.  Be certain to register the account as a managed account first at Central Administration -> Security -> Configure Managed Accounts.

SPTracev4 needs to be altered via a powershell command as detailed below:

Original source: http://blog.octavie.nl/index.php/2010/11/12/using-a-domain-account-for-sptracev4-service/

Run the powershell command to change the account to a domain user

1. # Get the tracing service.
2. $farm = Get-SPFarm
3. $tracingService = $farm.Services | where {$_.Name -eq “SPTraceV4”}
4. # Get the “svc_sp_services” managed account.
5. $managedAccount = Get-SPManagedAccount “Domain\account”
6. # Set the tracing service to run under the managed account.
7. $tracingService.ProcessIdentity.CurrentIdentityType = “SpecificUser”
8. $tracingService.ProcessIdentity.ManagedAccount = $managedAccount
9. $tracingService.ProcessIdentity.Update()
10. # This actually changes the “Run As” account of the Windows service.
11. $tracingService.ProcessIdentity.Deploy()

Add the domain user to the Performance Log Users group on all SharePoint servers.