Add the SQL Sentry monitoring service account to the Performance Monitor security group of the machine where the monitoring service is installed. For the service to access the Performance Counters of your watched instances remotely, grant the service account read access to certain registry keys. Complete the following steps on each target that you want to collect Performance Counters:
1. Navigate to the winreg key located at the following path:
2. Right click on the winreg key and select Permissions. Add the SQL Sentry monitoring service account.
3. Restart Windows.