Extract MSI Installer Packages with Open-source Lessmsi

So many software packages are available in form of MSI installers. MSI is a standard created by Microsoft and it can be used to package programs for installation on Windows PC. Now more and more software vendors have started to pack their programs inside MSI wrappers as it is easy to install on Windows. With MSI, we get many advantages such as well known silent installation switches. Now Mozilla is also releasing Firefox in form of a MSI installer package.

What if you want to extract the contents of an MSI package without actually installing it first? In that case, you can try an open-source tool called lessmsi. This is actually a short form of the full title of the program – Less MSIerables which again is fun rearrangement of letters of the popular Victor Hugo novel Les Miserables.

The program is offered in both the command line and graphical user interface versions. The command line version can be integrated with batch scripts or programs where you wish to extract the contents of an MSI package. The GUI can be used to extract one or more of the files from an MSI package. In addition, the GUI version of lessmsi also displays a wealth of other information.


As you load an MSI file in lessmsi GUI, it will display a list of all the files included in the package. Under the various other tabs, you can also find information such as the file table, summary of the MSI package and the streams. The summary for an MSI package shows information such as the title, keywords, author, comments, template, revision number, creation time, creating engine and more.

We can also add it to the right-click context-menu of Windows File Explorer. For this, we can launch the GUI version of lessmsi, select Edit and then Preferences. You will be presented with a tool using which you can integrate lessmsi in File Explorer. After this, we can right-click on any MSI file and extract its contents.


Overall, lessmsi does a great job. But there are some MSI packages (Firefox MSI for example) where it does not even display the contents. Perhaps it is because Firefox MSI packages are just the regular installer wrapped inside the MSI format. But nonetheless, lessmsi is very useful tool to extract MSI files on Windows.

You can download lessmsi from https://github.com/activescott/lessmsi.