In AX 2012 it is often necessary to read Excel files.
There are multiple ways to do this. The most widely used method is to use the Microsoft Excel COM objects. But if the file is to be read at the Application server or if the client is running on a terminal server it will not work.
In such cases you can install Excel on the AOS or the terminal server. But the most administrators will not be happy with this.
But there is a way to read XLSX-Files without Excel objects just by using open XML.