Hello Conrad
Thanks for your quick response.
I have done what you suggested, converting the path name of the secondary book fr om absolute to relative, and it works fine. In fact I'm using such a portable viewer right now to access my work machine from home.
I think, however, that there is a bug involved here. If, for whatever reason, the drive on which a secondary address book is stored (with an absolute pathname) is not accessible, then the address book manager will not open, and the viewer cannot be shut down normally. In both cases an error message is produced, and shut down has to be forced using task manager.
This happened to me originally when I moved a portable viewer on a USB drive to a different machine wh ere a different drive letter was assigned.
I have also tested it with an installed viewer, putting the secondary address book on a mapped network drive, closing the viewer, unmapping the drive, and re-opening the viewer. Similar errors then occurred opening the address book manager and closing the viewer.
On the other hand, if the file for a secondary address book is just renamed, moved, or deleted (perhaps by accident) then a simple file not found message is produced, address book manager can be opened, and the viewer can be shut down normally.