Hi,
I tried during the WE some deep investigations and tests:
- disabling some driver I was able to rebuild my windows 10 installation by the Microsoft official Windows 10 distribution, chosing to keep apps and files. It ended with a working O.S. but every app is not present, except the system apps (cortana and 3 more) that are located in \Windows\SystemApps\
- I used a new local user built only for tests
- I disabled firewall
- I got the ownership and permission as user logged on of hidden folder \Program Files\WindowsApps\
- I tried to reinstall store by the powershell commandlet that registers again the apps, using AppxManifest.xml. The system apps are registered correctly, other apps that are in folder \Program Files\WindowsApps\ ended with a generic error 404 of AppxDeployment-Server, saying that app manifest is not in the root. I checked and the file AppxManifest.xml IS in the root.
- I searched for hours in internet but I was not able to find anything related to apppackage server error 404
Keep going but it is really a mess.