The `msvcp120_app.dll` is associated with Microsoft Visual Studio 2013 and is a part of the Microsoft C Runtime Library, specifically designed for applications built using the Visual C++ component of Visual Studio 2013. The "msvcp" in the file name stands for Microsoft Visual C++ and "120" denotes the version corresponding to Visual Studio 2013. The "_app" suffix suggests that this DLL is tailored for applications, possibly indicating its use in Windows Store apps or Universal Windows Platform (UWP) apps developed with Visual Studio 2013. This DLL contains C++ standard library functions that are used by C++ applications. These functions cover a wide range of operations such as handling strings, files, and data structures, which are essential for the functioning of C++ applications. When developers build C++ applications with Visual Studio 2013, the application may rely on `msvcp120_app.dll` for these standard library functions.

If an application requires `msvcp120_app.dll` and this file is missing or corrupted on the system, the application may not run correctly, leading to error messages or crashes. Resolving issues related to this DLL typically involves reinstalling the Microsoft Visual C++ Redistributable Packages for Visual Studio 2013, which includes `msvcp120_app.dll` among other critical runtime components. It's crucial to ensure that these redistributable packages are installed correctly to support the smooth operation of C++ applications developed with Visual Studio 2013.