Python 3.5.0 offers a web installer. This implies that the other installer works offline. This is the case for the default component selection. When debug symbols/binaries are selected, the setup fails with error code 0x80070642 saying the user aborted the installation. This is a severe usability issue. Either everything should be included, or, if that makes the installer too big, "Install debugging symbols" should be "Download and install debugging symbols" - likewise "Install debug binaries" should be "Download and install debug binaries." When downloading fails, the failure message should mention that, rather than blaming the user for something they haven't done. Tested under Windows 7 SP1 X86 with the X86 non-web installer of Python 3.5.0.