The new version of the product contains new files and new components. If i run it in update mode, the new files doesn't get installed (regardless whether they are in a new component or in an old one). The installer ends without error messages, but the new files are not there.

If the old version is not installed, the installation will run correctly.
Do you have any idea about what causes this strange behavior and how can it be avoided?
Thanks for any input,
Medvekoma