Excel chrashes if you are perform following steps: 1. Create a new excel file. 2. Fill an excel cell with a any value. 3. Comment this cell. 4. Set the comment visible and move the position. 5. Remove the cell comment via POI method "cell.removeCellComment()". 6. Save the workbook to a new excel file. 7. Open the new generated excel file with Excel. Result: Excel CRASH!
This problem should be fixed in trunk. Please try with a nightly build - see download links on http://poi.apache.org/ or build yourself from SVN trunk, see http://poi.apache.org/subversion.html