Make sure InstallDirRegKey isn't setting $INSTDIR. InstallDir only sets the default value of $INSTDIR, in case no other values can be found. The priority of $INSTDIR
USB driver installer in NSIS - sverrirs.blog The USB driver I created for the Xbox Big Button Controller has been sorely lacking a decent installer. I finally decided on writing one in the Nullsoft Scriptable Install System or NSIS for short.. The NSIS system is incredibly powerful and quite easy to learn. I quickly learned however that creating a fully automatic installer for a Windows driver is very tricky. NSIS and Windows Installers for MultiUser (Current User) Apr 12, 2016 nsis: DSL for producing Windows Installer using NSIS. MUI2 by default: As NSIS has evolved there are now three separate ways to define your user interface, using the Classic builtin commands, using MUI1 or using MUI2. Of these, MUI2 is by far the nicest and should always be used, but the Classic interface is far easier to use.
Just have a look at them, you will see how the standard blue nsis.bmp starts off blue to the left then fades to a white, white is the standard color of the installer body, this color can be changed. Remember this trick when making your own, it's a way the images and the color settings of the installer body can blend different colors together.
Make sure InstallDirRegKey isn't setting $INSTDIR. InstallDir only sets the default value of $INSTDIR, in case no other values can be found. The priority of $INSTDIR Using NSIS To Make Installer Packages
Dec 24, 2015
NSIS Error - Microsoft Community Aug 08, 2017