Default settings of Windows 8/8.1 will let you install Windows apps without problems, but if you have modified your Windows 8.1 security settings or used a system tweaking software such as jv16 Power tools to enhance security settings, then you might probably end up not able to install Windows 8 apps.
In such scenarios, when you try to install a Windows 8 app from Windows Store, you will get error message “This app can’t be activated when UAC is disabled“.
To fix this problem, you have to change the UAC (User Account Control) of Windows as follows:
1. Move the mouse pointer to the bottom right corner of the screen to launch charms.
2. Click the magnifier icon t launch search.
3. Type UAC in the search box, and then click on Change User Account Control settings
4. Move the slider to the 3 spot from bottom Notify me only when apps try to mae changes to my computer (default). This is the default settings of Windows. System tweaking tools change it to Never notify condition, so causing the Explorer.EXE UAC error.
5. Click OK, and then restart your PC.
Now try installing Windows apps. Did it work for you? Do let us know in comments below.