This setting causes the Windows Installer to enforce strict rules for component upgrades - setting this may cause some updates to fail.
If you enable this policy setting strict upgrade rules will be enforced by the Windows Installer. Upgrades can fail if they attempt to do one of the following:
(1) Remove a component from a feature.
This can also occur if you change the GUID of a component. The component identified by the original GUID appears to be removed and the component as identified by the new GUID appears as a new component.
(2) Add a new feature to the top or middle of an existing feature tree.
The new feature must be added as a new leaf feature to an existing feature tree.
If you disable this policy setting, the Windows Installer will use less restrictive rules for component upgrades.