When installing Python 3.4 with the MSI, you can choose to install pip as part of the setup. With activated UAC on Windows (which is the recommended default), the installer will ask for elevated rights during the setup to copy the files over to the installation directory.

However, when the setup then attempts to install pip, the Python interpreter running the `ensurepip` library to install it is *not* run with elevated rights. This obviously results in a permission error when it then tries to copy over pip into the `\Scripts\` install directory.

This is similar to the advanced installer option “Compile .py files to byte code”, which has been failing forever because of the same problem. But now, with pip, this is an actual problem.

I suggest that you either run the pip install process from within the elevated setup, inheriting the rights—if that’s even possible—or explicitely request elevated rights for it again.