Setting up an RD license server has become easier in 2012 servers, but Microsoft still has a problem to solve. The only problem with the licensing server is that it is a single point of failure. In the event of maintenance or failure, devices that do not have an RDS-CAL per device or that do not have an RDS-CAL cannot connect until a new RD license server is running. In these situations, Microsoft recommends having a second RD license server (without CALs installed) and listing it as a second server in our VDI deployments. In this method, devices that do not yet have an RDS-CAL per device obtain temporary licenses in the event of a shutdown of the RD license primary server. The bad news is that devices with an expired CAL cannot connect until we reinstall the RDS CALs on the secondary server.