Microsoft does not offer the EXCEL.EXE (the object library) as a standalone download. This is because:
: The version number 12.0 corresponds strictly to Office 2007. Object libraries are version-dependent and require the corresponding desktop application to function. How to Acquire the Excel 12.0 Object Library microsoft office excel 12.0 object library download
: It contains documentation for all objects (Worksheets, Ranges, Workbooks), properties, and events within the Excel object model, enabling automation via languages like VBA, C#, or VB.NET. Microsoft does not offer the EXCEL
Because the library is an integral part of the software, you cannot download it as a separate patch. You can obtain it through the following methods: Technical Documentation | NetOffice Framework How to Acquire the Excel 12
Attempting to locate a "standalone" library file from third-party sources often leads to unsafe, unverified downloads. In almost all tested cases, the "missing" reference is resolved by correcting the Office installation rather than by downloading a foreign file.
The Excel 12.0 Object Library is into the core Excel 2007 application (EXCEL.EXE) itself and is installed as a direct, inseparable component of the software. It does not exist as an isolated .msi or .exe installer. As a result, the only official way to acquire the Microsoft Excel 12.0 Object Library is to have a licensed installation of Microsoft Office 2007 (or a version that includes Excel 2007) on the machine where you intend to develop or run your application.
When your development environment references this library, it gains access to Excel-specific objects, including: Controls the main Excel program instance.