Tips for Debugging Custom Actions in dotnet

Tip 1: For the message box make sure you give it a title or caption. For instance if you use MessageBox.Show() then use the overload that takes two strings as parameters. The first is the message in the message box. The second parameter is the caption. That's the important one since this is the string that you will find in the list of processes when you want to identify the right process.

Tip 2: In the dialog box for attaching the debugger to a process make sure you tick "Show processes from all users" as it might be that the msiexec.exe instance you are interested in is not displayed.