Hi Eryk,
I did think of that as well so I actually navigated to that temp folder (from the log) which the installer created (every time it runs, it creates a new temp folder and places the executable there) and executed that directly and got exactly the same log message.
So the folder exists, since the installer is creating it, and the .exe exists.
Armen

      From: Eryk Sun <report@bugs.python.org>
 To: alevonian@yahoo.com 
 Sent: Thursday, March 2, 2017 7:20 PM
 Subject: [issue29702] Error 0x80070003: Failed to launch elevated child process

Eryk Sun added the comment:

The error message is misleading. It happens that WiX is trying to run an elevated process (see the WiX functions CoreLaunchApprovedExe, CoreElevate, ElevationElevate, and PipeLaunchChildProcess). However, the actual error code has nothing to do with elevation. Error code 0x80070003 is a 32-bit HRESULT error originating from the Windows API (0x8007). The 16-bit Windows error is ERROR_PATH_NOT_FOUND (0x0003). According to the installation log, this error is from trying to shell execute "C:\Users\ALEVON~1\AppData\Local\Temp\{8D001A8F-7F1F-4183-A574-76127D642F75}\.be\python-3.5.3-amd64.exe". Notably the error is in the path instead of ERROR_FILE_NOT_FOUND (0x0002), so the problem may have been that one of the parent directories was missing.

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nosy: +eryksun

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<http://bugs.python.org/issue29702>
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