Hi wing1912, can you let me know how you updated your Little Math - did you uninstall the old version before installing the new one? If that's the case, then yes, the markers for "played" lessons would have been reset back to "not played."
If you have many lessons that you need to mark as "played," simply follow these steps:
1. Open Little Math and go to the Play & Edit screen, then select "Courses"
2. Select the Semester you are in. Make sure that all the "Day" folders are collapsed (closed) - if some folders are open, right-click on any folder and select "Expand/Collapse > Collapse All" from the menu
3. Select the first "Day" folder in the list, press and hold down your Shift key, then select the last "Day" folder that you've played before
4. Right-click on your selection then select "Mark Played" from the menu
I hope this helps!