WIX Custom Actions built for .Net Framework 4.0 does not work? Ways to resolve?

Question

We were using WIX 3.5 (Build Number 1811) and built a custom action built using Visual Studio 2008 and with target framework as .Net 3.5. This used to work great, until we b

Answer 1

There is a bug open to tweak the DTF supportedRuntime element in its manifest to support NETFX 4.0. That bug hasn't been fixed yet so you need still to do it yourself.

Answer 2

Just my two cents:

Unlike Ngm I only had to add supportedRuntime for .NET 4.0

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <startup useLegacyV2RuntimeActivationPolicy="true">
    <supportedRuntime version="v4.0" />
  </startup>
</configuration>

Important:

1. Don't rename CustomAction.config
2. Set the CustomAction.config Build Action to Content, else it won't work

Answer 3

Additionally to the solution from Ngm we had to set the target framework of the managed custom action class library back to .NET 2.0 to get things working.

Answer 4

Thanks for this nice post. Its solved my query. In my case error was I have renamed config file and now restored it to original.

Answer 5

Well we finally resolved the problem, we had to set:

useLegacyV2RuntimeActivationPolicy="true"
and
have both versions specified:
<supportedRuntime version="v2.0.50727"/>
and
<supportedRuntime version="v4.0"/>

If just "<supportedRuntime version="v4.0"/> is specified, it does not work. So looks like a bug in WIX 3.5 Beta