Are you facing a problem of failed uninstallation in your machine. Here is a tip to get it fixed.
When your MSI fails to uninstall because of an error or maybe because you have wrongly put a Custom Action to run at uninstall and it is failing. Even if you fix the error in your MSI by rebuilding it and try to install again, it will not work. This is because the maintenance mode will continue to use the cached version of MSI at Windows\Installer folder.
Many packaging people will suggest you to use third party utility like MSIZAP to completely remove the MSI. Though I won't say that's a bad option, but if we can make it work our MSI, that's preferable.
Here is what you need to do:
Fix the error in your package and set the REINSTALLMODE property to 'vomus'.
This will ensure it will run from the source package and re-cache the local package.