Thank you. Sadly the link didn't helped me. All my attempts with MSIX failed. But I solved it different now. I copied the manifest.xml file from MSIX and created it manually with the command line tool. The command line tool is better, since it reports the bug more detailed. By that I was able to hunt down the problem. There (in the manifest file and also in the Microsoft sample documentation) are a few missing lines in the manifest file. I added them and now I was able to create a package with the command line tool. Interestingly the same manifest file fails if pasted it into the GUI MSIX tool. But i didn't hunt that bug. After that I uploaded the package into the Microsoft App Store. Even there are a few strange tricks you need to know (for example I must check "Immersive headset", even I don't need it), but now my package was checked and is published by Microsoft. I downloaded and installed it. Works fine now. If anyone needs more detailed, I can explain it more detailed. I will mark it this topic as "solved" now.