问题
I am having issues installing a program by Cornelsen.
The setup dialog prompts that NET framework 4.0 is needed in order to install.
I have installed NET framework 4.8 and I have not found a way to downgrade.
Any idea on how to fix the prompt?
EDIT: @Filburt I have tried following your link and get this prompt
FIX: Thanks to @Stein Åsmul using SuperOrca and simply changing the RegLocator Value from .../1031 to .../1033 enabled the MSI to run.
回答1:
LaunchCondition: This looks like a regular MSI LaunchCondition. These are logical conditions that must be met (be true) for the installation to be allowed to proceed. You should be able to disable the condition by opening the MSI and removing the launch condition in question from the LaunchCondition table. You need an MSI tool to do so. Orca is Microsoft's own tool, it is installed with Visual Studio and the Windows SDK. Try searching for Orca-x86_en-us.msi - under Program Files (x86) and install the MSI you find, or maybe try SuperOrca.
Modifying MSI: You are supposed to create an MST (transform) to change an MSI file (essentially a database change fragment to apply to the original MSI database file at runtime), but you can "hotfix" an existing MSI if you are in a hurry. Make a zip or copy of the original MSI first. Then just delete offending entries from the LaunchCondition table. I suppose you can add "OR 1" to the existing condition as well - I think that should work to make the condition always true.
Error Condition: Removing a launch condition will allow you to install the MSI whilst the condition in question is not true, but it will not fix the actual error condition that your MSI is warning you about - you just suppress the error. In your case, you could try to install the German language pack for .NET 4.8 yourself first (that might even satisfy the current launch condition - I do not know): https://dotnet.microsoft.com/download/dotnet-framework/net48
来源：https://stackoverflow.com/questions/56348231/net-framework-4-0-install-fails