I have found where the Hour Guard Files are stored on a Mac
HD/Users/"Username"/Library/Application Support/HourGuard/
In this folder are:
Options.dat
Tasks Folder
Accounts Folder
Timesheets Folder
However the Timesheets Folder holds a neat trap for the unwary, as the .csv timesheets are stored in another folder called "Username"
So if you copy the HourGuard data folder from one Mac to another with the same "Username" you are fine, but change the "Username" and the Timesheets will disappear from view
Simple Fix
Create a Folder with your new "Username" and copy your files into it. Delete old "Username" folder
It worked for me
As usual Close the Application before messing with its innards and Back Up all data before toying with it.