This issue occurs when you haven't granted full access to the root folder  (NPK) to everyone.

Below is the pop up message that normally comes with it.

follow below process to resolve it

1.Go to NPK folder : ''C---->Program Files (x86) ----> NPK '', as per below screenshot

2.Go to NPK folder properties to give full access : right click on NPK folder and go to properties.

3.Go to security ----> Group or user names.Scroll down under group or user names  to look for  everyone . if it has been already defined.If not click on ''edit''.

4.Add everyone and give full access to this user, as per below screenshot.

5. Once you created and give all access, clik on "ok"