OK this is very odd... I do this: mkdir -p /mnt/MonetDB5/dbfarm merovingian monetdb create demo monetdb start demo and then start mclient: mclient -lsql --time --database=demo at that point everything is just fine and I can enter sql commands and all works great. I am using the default monetdb/monetdb for uname/pass. However once I exit out of this (\q) and try to go back in using the same command: mclient -lsql --time --database=demo It then comes back with: InvalidCredentialsException:checkCredentials:Invalid credentials for user 'monetdb' no matter how many times I try. So it works the very first time, but then not again. It seems like the very first onc to get a connection to the monetdb server is ok, but then any time after that it gets locked out somehow. What can be causing this? Also on a related note what is the monetdb5.secret file actually used for? I am also confused by this: # If you use Merovingian, a per-database vault key is used and this # setting ignored. #monet_vault_key=/etc/monetdb.secret So where then does the per-database vault key reside? And do I even need to mess with this? Thanks!