SearchIndexer.exe the process is the search service (or Indexing Service) of Windows. It is a service charge of exploring the contents of the hard drive to facilitate the search for a file on it.
However, this service can be a little heavy on resources (CPU, RAM, hard disk access) and can significantly slow down your computer. This is reflected mostly by a hard disk which is constant noise, even when the computer is not requested and a system that is slow to respond.
This document entitled « Searchindexer.exe » from CCM (ccm.net) is made available under the Creative Commons license. You can copy, modify copies of this page, under the conditions stipulated by the license, as this note appears clearly.