Alternatively you can have two installations of Copernicus use the same file. For this to work the user file would need to be stored on a medium that both computers have access to for example a network drive or removable media such as a floppy disk or CD. Using a removable medium has the added security advantage in that you can simply take your passwords with you.
NOTE: Copernicus is NOT designed for two instances to access the same user file at the same time. Read-only access would not cause any problems but each time one instance saved the file, it would overwrite changes that the other one made and vice-versa