The only sure way to test a backup is to restore it. Be careful however, that you do not restore the backup over the top of your working data in doing this.
1.Select the New/Open option from the Data menu on the Phoenix main menu bar
2.Select “New set of books”, click OK
3.Call the new folder “Test” and click "Create"
4.Insert the media (USB Memory Stick, etc.) with the backup on it
5.When the Select option for New Folder appears, select “Restore from backup” and click OK
6.In Restore Using, select "Drive"
7.Click the 
button and browse to the particular file you wish to restore.
8.Click Start Restore on the Restore Data window
9.Once the restore has finished verify the data restored is up-to-date and correct
Note that once you create the “Test” folder the first time, you do not need to create another each time you wish to test a backup. To test subsequent backups, first open the data in the existing Test folder, and then choose the Restore Option from the Data menu. Be very careful, however, that you only restore into the Test folder, and be sure you never enter new transactions in the Test folder.
See also: Restoring your Data
