If user had installed a product before and want to uninstall to reinstall same version but new build
sometimes the user need to delete the files manually from the installaton directory
so it is better for the product to force reinstallation for all the files , registry keys and others to avoid user undeletion
WIX support this by adding the follwing property to the Main fragment of the WIX project
<Property Id="REINSTALLMODE" Value="amus"/>
which mean:
a - Force all files to be reinstalled, regardless of version.
m - Rewrite all registry keys that go to HKEY_LOCAL_MACHINE or HKEY_CLASSES_ROOT.
u - Rewrite all registry keys that go to HKEY_CURRENT_USER or HKEY_USERS.
s - Reinstall shortcuts and icons.
