It can also happen when the permission is given, some folders aren't allowed for some reason. I had copied it from my computer to my phone's Documents folder and that did nothing when attempting to install, and I had to move it to another folder.
I'll make a note of this, thankyou. What folder did you move it to?
(Anecdotally, I had no problem from the Downloads folder.)
I copied it to a folder I had manually created.
