Had to reinstall w2k box (PDC+DNS). All w2k workstations lost their SID channels. (Next time I have to do this, is there any way to save the SAM?). Tried to reestablish trusting relationships with workstations by using "netdom remove" but always get "RPC unavailable or not started". RPC service is running and DNS-Netbios name conversions seem to work (at least all tests pass when doing netdiag /debug). Only way to reestablish SID channels is by creating new ones (ie. installing fresh w2k on workstations): then "netdom verify" does good. Otherwise, I ALWAYS get "RPC unavailable" or similar, no matter what I try. No clue on how to establish a trusting relationship other than domain-domain type from a MMC. Can't reinstall OS on all workstations, that's a big torture. Anyone can help?. God bless