title: How to avoid install same instance of application wix installer MSI & EXE?
body: <p>I have an MSI &amp; EXE installer that installs the excel plug-in. The user has option to download exe or msi to install the plug-in. The problem is my applicaiton shows a notification to user if new version of applicaiton is available and if user  get new version I always returns the msi file because at that point I don't have any information that user has installed the plug-in through msi or .exe. If user install thorugh exe and install new version with msi the multipe instance installed on same machine. How I can avoid it?</p>
  <p>Also, is there any way in C# to know the applicaiton is installed through msi or exe?</p>