we've tried to write an Office 2007 .xlsx from java with Apose.Cells. When we try to open the file, Excel says, that there is some unreadable content on line 2636, column 44 and line 27, colum 43. However, we don't write any content to these cells. I have taken a look at sheet1.xml, everything looks fine in there.
I will attach the generated file and a simplified code sample we use for generation. The same code works fine for Excel 2000 files.
Hopefully, someone can help.