Hello,
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If I understand you correctly, you want to create a system cleaner app using UWP, right?
UWP application is a sandbox application, which is located in an isolated environment at runtime. In principle, UWP applications do not interfere with each other and can only communicate in a limited number of ways and UWP applications could not reading the registry as well.
So if you want to develop system cleaning related applications, it might be better to use some other techniques like traditional desktop apps.
Thanks.