When double-clicking packageappx.manifest, it says:
Error HRESULT E_FAIL has been returned from a call to a COM component.
This is after a fresh export from Construct 2 to make a Windows 10 app. I Googled the issue, but every solution doesn't seem to apply to my case, or is only for programmers to understand. I only have a few days to pass this issue before the Windows Creators UWA contest deadline on Nov 17.
UPDATE: It looks like I did it! If it's not too early to celebrate: Here's what I did: I downloaded and installed the latest "Visual Studio Community 2017 Preview" 15.5.0 Preview 3.0, and I also Modified the Install by checkmarking "Universal Windows Platform development" and "Desktop development with C++" including all the Individual component Windows 10 SDKs. Doing it in that is what did it.