problem with xlsx file with pivot

Oct 22, 2016 at 5:32 PM
I'm using NPOI 2.2.1. I open an xlsx with a Pivot table, I write some values in some cells an than save the file.
After that if I open the file with Excel I have the following errors:

/xl/pivotCache/pivotCacheDefinition1.xml with error XML. (cache pivot table).

What I can do?