I am installing python 3.5.0a3 first time on windows 8.1 64 bit and at the starting of installation, it just says "Setup failed".

Here is the log file.

python setup error

  • the logs shows that Update KB2999226 fails to install. This seams to be a private hotfix. Apr 24, 2015 at 17:10
  • Is it any windows Update ?
    – Bhavesh G
    Apr 24, 2015 at 18:53
  • 1
    it seams to be a private hotfix, because the KB page (support.microsoft.com/en-us/kb/2999226/en-us) is not shown. I have no idea why python includes this hotfix. In the log I can see that the 64Bit MSU updates was tried to be installed by a 32Bit WUSA, which may cause the issue. Ask this the python guys, who created the installer. Apr 25, 2015 at 6:33

3 Answers 3


Got the same error after lot of research i found the below thing...It works like a charm..100% worked for me

First...Make sure to check the setup package for your system that is X86 or x64, download packages based on the system before you proceed, otherwise the hack wont work. The below is explained for x64 bit windows 8.1 system with a 64 bit Python setup package use the below mentioned setup name(.exe file) in Step1: and search in google for downloading the Python setup

if the following error comes while installing Python 3.5.0 Setup in windows 8.1 64 bit Operating Sys- Error 0x80240017: Failed to configure per-machine MSU package

Start CMD as Admin, after that

Step1: ~YourFilePath/python-3.5.0-amd64.exe /quiet InstallAllUsers=1 PrependPath=1 Include_test=0

Step2: ~YourFilePath/python-3.5.0-amd64.exe

~YourFilePath stands for the location of the python-3.5.0-amd64.exe file in your PC Example: E:\Softwares\python-3.5.0-amd64.exe

now after executing the Step2: the setup will run without any errors..... Cool....

The above mentioned steps should work or else If you find any difficulties please visit here which explains the process in detail. Good Luck...


Got the same message error while trying to install Python 3.5.0 (released 2015-09-15) on Windows 8.1 64-bit.

Two solutions :


Run as Administrate and UN-check recommended installation

  • 2
    Hi and welcome to Super User! Thanks for taking the time to answer this question. Unfortunately, this answer isn't particularly clear about the steps that need to be taken (e.g. how would one go about running this as an Administrator, what do you mean by "uncheck recommended installation", etc.) Please consider expanding your instructions to include these relevant details or other useful information (such as screenshots of the options you are describing, etc, etc.) Nov 8, 2019 at 3:11

Not the answer you're looking for? Browse other questions tagged or ask your own question.