title: Editing an existing excel in C# with NPOI
body: <p>I need some help to solve an issue I'm facing using NPOI 2.3
  I've created an excel with 1 jpeg picture and some shapes (just to group the fields)</p>
  
  <p>In some cell I've put a value that starts with ## 
  I need to open the excel, replace cell containing ## with correct values coming from db and save the result.
  All works well except when I try to reopen the modified xslx file I got an error about Drawing shape corrupted. The values are ok but all shapes and the picture are removed.</p>
  
  <p>Here you can find the link <a href="https://1drv.ms/x/s!AigFpWk8h0GOgP9qoGKhEvUCXiy2bQ" rel="nofollow noreferrer">TemplateFile</a>
  Can someone helps me to identify the problem ?
  Many thanks
  Fab</p>