hi, we have a windows 2003 (with SP1) DC ( termed as PDC) and an additional windows 2003 DC (termed as BDC). the PDC holds the GC and is also running Exchange server 2003 (with SP1). Recently, we identified this problem with the PDC that it gives RPC errors on the workstations or other serves which are attempted to join the domain. But when the BDC is turned on, everything works fine. this has given us a clue that something is wrong on the PDC and we need to fix it. When a computer is joined to the domain, it asks for the user id/password which is authenticated and then following error appears after a while : "The remote procedure call failed" can anyone please give me a clue whta might be causing this ? thanks ! akhlaq