A lot of customers have recently started seeing the following errors, all stating in various ways that Microsoft .NET Framework 2.0 Service Pack 1 failed to install. You may also see this when attempting to install other updates on top of .NET 2.0 SP1.
Debugging custom actions isn’t exactly the easiest action to do; Windows Installer spawns separate processes – remoting servers – to run in-process custom actions. Any opportunity to diagnose issues without debugging can be helpful.
For example, an issue that comes up from time to time is leaked handles.