Question

I have just started using NSIS.
It works very well but I find the documentation a bit unstructured. How do I require user to uninstall previous version before installing a new version with NSIS?

NSIS (Nullsoft Scriptable Install System) is an open source system to create Windows installers.

Answer 1

NSIS is a great Windows Installer. Here is how I use NSIS to uninstall the current version while installing a new version of the same application. Add the following function to your NSIS script.

Function .onInit           Exec $INSTDIR\uninst.exe   FunctionEnd 

Also you can check out this link on the NSIS wiki on ‘Auto-uninstall old before installing new’.