CU5 crashed while installing on one of our 4 DAG members. I was able to coax it back to life with some manual steps and doing a repair of sp1, but was unable to get cu5 to install or to cleanly uninstall sp1 despite repeated tries.
Finally I decided to rebuild it and use recoverserver (after removing database copies and removing it from the DAG). I built a new server with the same name, reset the AD account, domain joined it, and then ran the /recoverserver switch. But I get this error every time:
"Can't specify installation mode because no Exchange Server is installed on this machine. Install Exchange Server."
