EXFO FTB-500 (Window XP) - Manual (Page 130)

Using the Optional Built-In Power Meter and VFL
120 FTB-500
Opening Results Files
3. From the given list of files, select the file to open.
4. Confirm with Open.
If you have already performed power measurements, but not saved
them, the application will prompt you to save your work. You must
either save or discard the unsaved measurements before being able to
open a file.
5. To view the reopened file, go to the Measurements tab. The power or
loss measurements are displayed on the results list.