MSI files are database files (specifically MS-SQL databases) which describe the installation via database tables and install via a complex set of installation sequences defined within the MSI file itself. What makes MSI special is that it's included with and interpreted by built-in tools, and it is also integrated into Active Directory for easier deployment across many machines in a corporate environment, and Clem's answer covers that in more detail. You could in theory create any exe that uses a database similar to MSI (and NSIS, InnoSetup, etc., do something similar). This interpreter will then follow the steps laid out in the MSI file.

By itself, it is not executable it is actually interpreted by msiexec.exe on Windows systems. MSI is a specific format used to store information about an installation, a database of what steps to take and which files to put where. Others use installer generators to save some time and effort these include NSIS, InnoSetup, InstallShield and more. Some people write their own custom installers. Of course, with arbitrary machine code you are able to write an installer - and those 'exe' installers you see take that approach.

There is nothing about the PE format that will identify it as an installer. There is no universal installer standard or format any program that performs these actions ('installs' another program) may be called an installer.Īn 'exe' file in Windows is known as the Portable Executable file, and contains arbitrary instructions, either native machine code or. During this process, an installer (on Windows) might copy files into system locations, place shortcuts to launch it, update libraries, remove older versions, etc. What is an installer? Well, an installer prepares a system to allow a program to run: it installs that program.

Advanced installer msi to exe