I have a UltraGrid, populated with cca 22.000 rows and and 10 columns at most (It never breaks 65536 barrier). When I export the contents of the grid to excel file, everything goes well, but when I want to open file with excel, it gives me following notification:

Excel found unreadable content in 'export.xls'. Do you want to recover the contents of this workbook? If you trust the source of this workbook, click Yes.

When I click Yes, it tries to repair the damage but is unable to do it. The only column whose value gets exported is the one that is of type boolean.

I am using NetAdvantage for .NET 2007 Vol. 3 CLR 2.0 with latest (1043) patch applied. What could possibly cause this error? Column types are mainly strings and integers with the exception of one Guid and abovementioned boolean. I use no intermediate features of grid (ie calculated columns, summaries, etc.). It is simply a ultragrid bound to datasource. In all other cases throughout my application everything works fine with the exception of this grid which contains quite a lot of rows.

Best regards.