Seemingly empty file after adding 'too many' rows

[mareklipka]

I create my xls file by iterating over some objects and making subsequent rows with Spreadsheet#update_row method. The problem is, after I add 'too many' (which is about 10) rows, the file (although it contains 13kb of data - so it's not very big, but it's not empty either) seems to be completely empty after I open it in some xls editor. Is it some kind of known artifact? How do I solve this?

[zdavatz]

1. What OS are you using?
2. Please share your code.
3. Which software created the original file that you are now editing with spreadsheet?