Thank you
It installed to the newly created directorey on the D drive and was present. Then I installed the Nik Collection, also in a specifically created directory on D drive, Affinity Photo 2 as the host application. When working on images in AP2, Nik plugins suddenly did not open anymore (after the third image), and I got the warning of not enough space. Then I saw, that AP2 was again on the C drive. It's strange that the file directory on D indeed contains the Nik Collection, but the Apps and Features in Windows preferences show iton the C drive. Then I deinstalled AP2 (exe file), reinstalled the MSIX-file on C (default) and transferred it to D, where I am unable to locate it.