These are perfectly normal and are part of Microsoft’s new software
signature checking system. After installing the PMDG 747-400X, you will
see three pop-up alerts asking if you wish to run dlls that are signed
by PMDG. These are the PMDG modules files. You will then see four more
when you actually load the PMDG 747-400X aircraft for the first time.
These are the gauges. Just select ok/allow for all of them and
everything will work.
If you select NO to any of them your PMDG product will not work and
you may be required to uninstall the PMDG 747-400X and re-install in
order to use this product.