Solving install issues with Python 3.4 on Windows

Question

I have recently tried to install Python 3.4 as an alternative installation on my system in an attempt to familiarise myself before migrating code. My main Python installation is 2.7.6.

I tried the 64 bit installer for Windows, but it came up with an error message

There is a problem with this Windows Installer package. A program run as part of the setup did not finish as expected. Contact your support personnel or package vendor.

After this the install is rolled back (from the point shown below):

I have eventually found a solution to this posted below and decided to share in case anyone else was having the same issue.

Answer 1

I faced this issue because of 2 conflicting versions of 7zip. Removing them both and installing just one fixed this issue.

Answer 2

My issue was that I had a PYTHON_HOME or PYTHON_SOMETHING environment variable set. After removing the environment variable, the installation worked perfectly.

Answer 3

Mine was linked to having installed an older version in the past, only for my own user account. I got around it by telling the installer to install Python for all users.

Answer 4

What worked for me, strangely enough, was the "Microsoft Program Install and Uninstall troubleshooter"

The "deselect pip" solution did not work for me.

My Python 3.4.1 install was failing with the same "A program run as part of the setup did not finish as expected" error. I tried both installing it on top of Python 3.4.0 and installing it in a new folder, but got the same error. I tried uninstalling Python 3.4.0 first, but got the error during the uninstall, as well.

I ran that Microsoft utility, which helped me uninstall 3.4.0, and was then able to install 3.4.1 cleanly. The utility has options for both problematic installs and uninstalls, so it may help even if you're doing a new install, not an upgrade.

I'm running 64-bit Windows 7, but was working with 32-bit Python versions.

Answer 5

I had python3.4 installed, then added 3.5, and deleted 3.4. That was a mistake. In trying to get a library to work, I had to go back to 3.4. I uninstalled 3.5, but couldn't uninstall 3.4 (folder deleted).

I ended up searching the registry in rededt32 for "python". There was a Guid folder with a number of entries that had c:\python34 and one more related to the same folder that I deleted. After this, the install worked correctly.

Windows 10.

Answer 6

According to me when environment variables containing name 'Python' are created they somehow becomes related with python. I was unable to open idle (GUI PUTHON) and to uninstall it . Deleting a variable named 'PYTHON PATH' solved my all python related problems.