With counsel from Bramley in the MacOSXHints.com System forum, I developed an application that automatically unmounts my backup internal hard drive's 10.3.4 volume on startup. This prevents alias confusion in opening files on the wrong internal hard drive after Retrospect 6 Duplication cloning. My hunch is that the clone's files initially look more recent than the working drive's files to the OS and/or applications used to open the files.
There may have been other causal factors, but after adding the second internal hard drive and duplicating to it periodically, Office X and then Office 2004 Entourage opened the cloned database rather than automatically opening the one on its own drive.
Now, when I wish to duplicate/clone the working hard drive to the backup drive, I just run another script that mounts my destination volume, runs the customized duplication script, and then unmounts the volume. On the next login after duplication, I am secure in the knowledge that the backup volumes will be unmounted without having to rely on human memory. Here's how: Open AppleScript editor and enter:
tell application "Finder"
if exists (disk "Name of Backup Volume") then
eject "Name of Backup Volume"
else
display dialog "volume not found or is unmounted already"
end if
end tell
"Save as" and then scroll in the format pop-up menu to "Application." Uncheck the default "startup screen" box in the save-as dialogue. Make sure saved in Applications folder. Then open System Preferences/Accounts/Start Up Items and add it.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20040624012142602