A: First, if you’re upgrading from the beta of System Center Operations Manager 2012 (SCOM 2012) to the release candidate (RC), make sure you download the RC documentation and follow the deployment guide for the steps to perform the upgrade.
For the Data Access Service account, the best practice is not to use Local System for the Operations Manager services but instead to use a domain account.
To check what account you previously configured when you installed the beta, launch services.msc and look at the properties of System Center Data Access Service. Look at the Log On tab, which displays the account you currently have configured for the beta so you can use the same again during the RC upgrade. See the screen shot below.