why do my powerpoint charts revert back to old data?

[KL]

I'm trying to update powerpoint charts and everytime I move onto the next
slide and then go back to the first slide the data has changed back to the
original data.

Does anyone know why?

 

[Echo S]

You might try round-tripping through HTML to weed out the willies.

http://www.pptworkbench.com/html/round_trip.htm has good instrux.