What are the specific differences between .msi and setup.exe file?

210
votes

I searched a lot, but all are guessed answers. Help me to find the exact answer.

4
windows-servicesinstallationwindows-installer
see stackoverflow.com/questions/902841/… – rds
Here is a more recent answer – Stein Åsmul
I wanted to install a program that came with both an EXE and MSI installer. I first installed from MSI, which only installed the program files (not any prerequisites or dependencies, and didn't create Start Menu icons). When I manually launched the program, it failed saying certain DLLs were missing. Installing from the EXE installed other things too, and the product ran just fine. I would say, if a software maker provides both an EXE and MSI option for installing, use the EXE. – James L.

4 Answers

257
votes

An MSI is a Windows Installer database. Windows Installer (a service installed with Windows) uses this to install software on your system (i.e. copy files, set registry values, etc...).

A setup.exe may either be a bootstrapper or a non-msi installer. A non-msi installer will extract the installation resources from itself and manage their installation directly. A bootstrapper will contain an MSI instead of individual files. In this case, the setup.exe will call Windows Installer to install the MSI.

Some reasons you might want to use a setup.exe:

  • Windows Installer only allows one MSI to be installing at a time. This means that it is difficult to have an MSI install other MSIs (e.g. dependencies like the .NET framework or C++ runtime). Since a setup.exe is not an MSI, it can be used to install several MSIs in sequence.
  • You might want more precise control over how the installation is managed. An MSI has very specific rules about how it manages the installations, including installing, upgrading, and uninstalling. A setup.exe gives complete control over the software configuration process. This should only be done if you really need the extra control since it is a lot of work, and it can be tricky to get it right.
14
votes

.msi files are windows installer files without the windows installer runtime, setup.exe can be any executable programm (probably one that installs stuff on your computer)

9
votes

MSI is an installer file which installs your program on the executing system.

Setup.exe is an application (executable file) which has msi file(s) as its one of the resources. Executing Setup.exe will in turn execute msi (the installer) which writes your application to the system.

Edit (as suggested in comment): Setup executable files don't necessarily have an MSI resource internally

-11
votes

MSI is basically an installer from Microsoft that is built into windows. It associates components with features and contains installation control information. It is not necessary that this file contains actual user required files i.e the application programs which user expects. MSI can contain another setup.exe inside it which the MSI wraps, which actually contains the user required files.

Hope this clears you doubt.