I was just being a bit dull, I'm afraid - I've had a read of the psql help, and by default it connects to port 5432, which is the port that's listening for the PG 8.1.4 install on my server. I ran 'bin/psql -p 5555' instead, to point at my PG 9.0 instance, and the pg_start_backup worked fine. Thanks to all! Dan -- View this message in context: http://postgresql.1045698.n5.nabble.com/Can-t-take-base-back-up-with-Postgres-9-0-on-Solaris-10-tp3240364p3240641.html Sent from the PostgreSQL - general mailing list archive at Nabble.com. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general