I have successfully installed the HUB and CAS servers.Ran the following command to install the mailbox role, tools and CMSsetup /m:install /roles:mailbox /domaincontroller:<DC Name>/t:d:\exchange /newcms /cmsname:<CMS Name> /cmsipaddress:<CMS IP> /cmssharedstorage /cmsdatapath:r:\mountpointsAll installed except the CMS with errors list below; Clustered Mailbox Server ......................... FAILED Setup cannot continue because the RPC server is unavailable. This could be due to DNS information for clustered mailbox server '<Svr Name>' has not finished replicating. Run Setup again after DNS replication has completed. You can verify that DNS replication has completed by running "nslookup <svr name>resolved via nslookup. I uninstalled, performed detailed clean-up, force replicated then tried againSame issue.

Check info: 1. Please go to application log, see if theres any related error event 2. Please describe more about exchange topology, windows server version and so on 3. Please verify that we can ping through nodes 4. Please find failed installation log, go to the point where also shows the error info Setup cannot continue because the RPC server is unavailable, check the context that surrounds the error. Those info can tell us where failure happens 5. Please run ExBPA against problematic node for health check Troubleshooting: 1. Please use the step 1 in the Resolution section of KB 871111, make sure that Dynamic updates has set to Secure Only in the DNS server 2. Please go to Cluster Administrator, if theres any offline resources, try to take them online 3. Please check the DNS for clustered mailbox server [CMS], verify if theres a DNS entry for CMS. If theres no DNS host record for CMS, please create one and install again