(This works in projects that use MSI as the installation engine, I don't know enough about pure Installscript projects to help you there) Honestly, I find the prequisite Installer too complicated to use it for installing .NET packages and I kept running in the same problems. It also doesn't make sense to me to install additional packages before your Setup (except when your Custom Actions need .NET themselves). I rather run the required package AFTER I'm sure my  own installation had run successfully. This is what I do: Get the online or offline .NET Installer you need from https://docs.microsoft.com/en-us/dotnet/framework/deployment/deployment-guide-for-developers#redistributable-packages and store it in a persistent location Add a System Search for the Registry Key like https://docs.microsoft.com/en-us/dotnet/framework/deployment/deployment-guide-for-developers#detecting-the-net-framework and save the result in a Property, eg PROP_DOTNET_INSTALLED_VERSION. Also make note of the DWORD Version of .Net Framework you require (In your case, 4.7.2 -> 461808) Add a new Custom Action EXE->Stored in Binary Table and add the Exe file you just downloaded  Add the following string to the "Command Line"-Option in your Custom Action : "/passive /norestart /showrmui /LCID [ProductLanguage]" (no quotes) This will show a passive progress dialog of the .Net installation. Use "/q /norestart /showrmui" (no quotes) instead if you don't want to show anything to the user Run the CustomAction after "InstallFinalize" and execute it when the .Net Version from the Registry Key is lower than the one you require (in your case this would be: NOT REMOVE~="ALL" AND NOT PROP_DOTNET_INSTALLED_VERSION >= 461808) Depending on your setup design, you can(should?) add a Checkbox in your dialogue so the user can decide if he wants to install missing .NET during the setup or all by himself afterwards. ... View more