App can't be opened using the built-in administrator account.

Kari said:

Please tell did you clean install Windows 10 or upgrade from Windows 7? Some Windows 7 users decided that they do not need stupid Microsoft to tell them what they can do and what not, and feeling like Masters of the Universe they enabled built-in admin account using it as their only user account. A stupid thing to do, of course.

These users will automatically get issues when upgrading to Windows 10; the upgrade process sees an existing user account not detecting it is the built-in admin, upgrading to 10. Because Windows 8 and later use MS accounts, too, the system has evolved and you simply cannot use built-in admin anymore as your daily, only user account.

If that's your case then my sincere advice and recommendation is to clean install Windows 10.

I built PC from scratch and booted from Windows 10 USB. Clean instal. What not clean could I have done?

Kari said:

OK, that's good.

My previous post told the only possible scenario leading to situation where Windows 10 is directly after installation using built-in admin account as a normal user account without user specifically enabling it: Upgrade started from Windows 7 when signed in as built-in admin. That upgrade route only leads to issues. As your user account according what you have told is somehow built-in admin, I wanted to either confirm you did upgrade from Windows 7 using built-in admin, or completely exclude that option.

I see no other reasonable option than to start from scratch, clean install.

At least you try to understand my problem and help me, not like those stack exchange a******s who downvote everything

I was getting UAC shields appearing on some of the icons. I found the solution how to get rid of them by going to the "Local Security Policy" > Local Policies > Security Options and disabling:
User Account Control: Run all administrators in Admin Approval Mode
User Account Control: Admin Approval Mode for the Built-in Administrator account

And of course I ran into the bigger issue. I can't open any windows related app. This is what is says (see above). If I re-enable the policy, the programs work again, but the shields appear again. I really don't want them and they bother me and as far as I have researched this is the only solution I found that is working.
Now back to the blue message. I have tried creating a new user and giving it admin rights. Still got the blue message. Then I tried disabling the built-in administrator with this method here. Restarted PC, still the same result.
I really ran out of options. Can somebody smarter than me please help me resolve this problem.
I'm running Windows 10 Pro.
My Local Security Policy list here

P.S. I did not upgrage to Windows 10 from earlier versions, I built PC from scratch and booted from usb.

Follow up!
People have suggested me to reinstall windows/do a clean install. So I did create a new bootable usb with completely different build and got the same result.

I think that this is a huge flaw with windows 10 and I'm really looking forward to solving this issue. Smartest people here please help me!
Also note that I'm not using Built-in administrator account. I'm local Administrator.

Kari said:

OK, now I understand what's going on, having reproduced your scenario and tested it. Have learned something new, too.

By disabling the Admin Approval Mode for the Built-in administrator account, you in effect switched your local admin account to built-in admin account. It still is a local admin account but when running applications it runs all of them, without a possibility for you to change it, in elevated admin mode. That naturally makes it impossible to use Windows Store apps because they cannot be run as built-in admin, elevated.

Enable the security policy to be able to run Windows apps.

Kari

Yeah....it sucks, because when I re-enable it, blue/yellow shields appear and this happens whenever I want to change something (ex. change icon).

It is also interesting that the shields and prompts disappear only if you disable both of these:
User Account Control: Run all administrators in Admin Approval Mode
User Account Control: Admin Approval Mode for the Built-in Administrator account

The entire problem starts with the shield overlay on "some" icons and when you are trying to get rid of them as they are annoying to say the least.
The shield overlay on an icon normally tells you that there are restrictions in using the program behind the icon.
The problem is that the overlay does appear irregular and not depending on your account. This irregular appearance is for me a Windows 10 bug which already existed since Windows 8.0 (and maybe before, can't remember that far back).
Sometimes they are there after in installation of a program, sometimes they only appear after a reboot, sometimes they appear after an update etc... and it doesn't matter if you have an administrator account or not, even if you have only one account on your PC with full admin rights they appear on some programs, no matter how you install the program or if you turned UAC off or on.

This shield is annoying because it "destroy's" the beauty of the icon.
One solution found on the net to get rid of them is the UAC: Admin Approval Mode for the built in Admin Account.
But that leaves you with the topic starters problem.

But there's another solution, you can use the same trick as used to get rid of the shortcut arrow.
I haven't found a free one yet to do so (they only offer the option to remove the shortcut arrow) but the payware MircoAngelo On Display offers the option to remove the shield icon.

Mind that this does not change the behaviour of the icon. If it originally had a shield on it, it will come with restrictions. These user restrictions are still there, only the overlay is removed.