You may have upgraded your project to target Office 2016/2019, but a third-party library (like a reporting tool or a data grid component) was compiled against the older 15.0.0.0 assemblies. Your application loads fine, but when that specific library tries to instantiate an Excel Application object, the runtime searches for the old version.
One of the most common runtime errors with version 15.0.0.0 is: microsoft.office.interop.excel version 15.0.0.0
Excel.Application excelApp = null; Excel.Workbook workbook = null; Excel.Worksheet worksheet = null; You may have upgraded your project to target
Compile against the lowest version of Office you intend to support. If your customers use both Excel 2013 and 2016, targeting version 15.0.0.0 is safe. If they use Excel 2010, you should target version 14.0.0.0 instead. If your customers use both Excel 2013 and
One of the most confusing aspects for developers is forward/backward compatibility. Here’s how Microsoft.Office.Interop.Excel version 15.0.0.0 behaves with different Excel installations:
// Release COM objects properly if (worksheet != null) System.Runtime.InteropServices.Marshal.ReleaseComObject(worksheet); if (workbook != null) System.Runtime.InteropServices.Marshal.ReleaseComObject(workbook); if (excelApp != null) System.Runtime.InteropServices.Marshal.ReleaseComObject(excelApp);
| Metadata | Value | |----------|-------| | | Microsoft.Office.Interop.Excel | | Version | 15.0.0.0 | | Corresponding Office Version | Microsoft Office 2013 | | File Version | 15.0.4420.1017 (common build) | | Public Key Token | 71e9bce111e9429c | | Culture | neutral | | Processor Architecture | MSIL (AnyCPU) | | COM Wrapper Type | Primary Interop Assembly (PIA) |