# XlsxWriteException ```csharp public sealed class XlsxWriteException : InvalidOperationException ``` Namespace `SharpCell.Xlsx` · package `SharpCell.Xlsx` A workbook was not saved because SharpCell could not calculate some of its formulas; see [XlsxWriteOptions.KeepUncalculated](SharpCell.Xlsx.XlsxWriteOptions.md#keepuncalculated). ## Properties ### Problems ```csharp public IReadOnlyList Problems { get; } ``` The formula cells that could not be calculated, with the reason for each.