Basically if you use system imaging tools or you have a recovery sector this may be why you see it

The file halmacpi.dll has been developed to function under UMR Desktop System Preparation (Sysprep) Tool and Sysprep Hardware Abstraction Layers. These dual Syspreps are central in building the image of a system.

The file halmacpi.dll is related to the usage of the Microsoft Developer Network (MSDN) Library with Operating Systems. The MSDN Library is the de jure resource for developers that use Microsoft products, tools and technologies. It contains full developer support in the form of programming information, including sample codes, documentation, technical articles, dictionary tables, and chart guides.

A part of the module halmacpi.dll’s filename is derived from the acronym HAL standing for Hardware Abstraction Layer. HAL also works as a software project that allows desktop applications on an operating system to readily access hardware information. With this function, hardware can be located and used regardless of the bus or device type. To optimize the performance of the file halmacpi.dll, this file should be registered first into the computer system. This can be done through the use of programs geared to perform the said task or through keying in the proper commands in the run or command window.

Advanced Configuration and Power Interface (ACPI) establishes industry-standard interfaces that enable OS-directed configuration, power management, and thermal management of mobile, desktop, and server platforms. The said parts are required to perform computer generated system deployment that utilizes an ACPI Multiprocessor PC integrated with aforementioned ACPI and HAL. This triggered the need and creation of the file halmacpi.dll.