Property Value

Type: Boolean
true if the any unmanaged customizations that have been applied over existing managed solution components should be overwritten; otherwise, false.

This setting applies to scenarios where the managed solution is already installed and it is being installed again, perhaps as a newer version. When this value is false importing the solution will only update the managed solution components and any unmanaged customizations of those components will remain. By setting this property to true and importing the solution, any unmanaged customizations will be overwritten. You may want to do this as a way to re-initialize the solution.

Note
To preserve any unmanaged customizations, export any unmanaged customizations before installing the update with this option set to true.