A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
This not a link to fix the problem merely a Microsoft guide how to use graphs. The graphs are established, printed and the document saved. Then when you make a change anywhere in the Excel worksheet then randomly the graph data get erased from either completely the graph, most data series, or a single data series kept but referring to only one cell.
This link as mentioned does not lead to a solution. Best be removed as it only serves to delay solution to what has been reported as an Excel issue since version 2010 that Microsoft has failed to address. It maybe the result of trial versions of Excel having graphing functions disabled even when upgraded to full versions, as the only solution I have seen has been complete removal of Excel, manually editing the Registry to remove any trace of Office, and then reinstalling. Surely Microsoft can come up with a better solution to a problem it has caused trying to push sell its products.