Backups when original is on encrypted volume, how?

[Jeff Earickson]

All,

I am paranoid, so I keep my Gnucash files on an encrypted Mac OS volume.
To use Gnucash, I unplug the Ethernet cable, decrypt the volume, go do my
Gnucash work, unmount the volume.

Before unmounting the volume, I have been saving my Gnucash folder to a
thumbdrive as a backup.  I have discovered that the backup does not work
unless the encrypted volume is mounted.  With no encrypted volume, I get
the message "The file file:///Volumes/encrypted/gnucash/mydata.gnucash
could not be found."

How do I make a backup of my Gnucash data so that a restore will work when
the original volume is gone?  Does the .gnucash directory in my homedir
factor into how this works?

Jeff Earickson