If I run an INCREMENTAL * backup nightly and the Domino admin turns on
circular logging, does that INCREMENTAL still function the way it did, or
does it now switch over and not back up the database becuase is it "logged"
even though it is circular logging and I can't archive those logs?

I have a client that has been running the INCREMENTAL now for years and last
fall the Domino admin turned on circular logging. Now the nightly
incremental only does a handful of databases.

Bill Boyer
"An Optimist is just a pessimist with no job experience."  - Scott Adams