The Windows x86-64 MSI Installer (python-3.4.0.amd64.msi, python-3.3.4.amd64.msi...) does not install python3X.dll in windows\system32 or windows\SysWOW64 folder.

I select an option "install for all users"

Windows 7 64 bit 

(The Windows x86 MSI installer works fine.)

Python installation log included.

MSI (s) (48:2C) [01:28:13:006]: Executing op: SetTargetFolder(Folder=C:\Windows\system32\)
MSI (s) (48:2C) [01:28:13:006]: Executing op: SetSourceFolder(Folder=1\)
MSI (s) (48:2C) [01:28:13:006]: Executing op: FileCopy(SourceName=PYTHON34.DLL|python34.dll,SourceCabKey=python34.dll,DestName=python34.dll,Attributes=512,FileSize=4044800,PerTick=65536,,VerifyMedia=1,,,,,CheckCRC=0,Version=3.4.150.1013,Language=0,InstallMode=58982400,,,,,,,)
MSI (s) (48:2C) [01:28:13:007]: File: C:\Windows\system32\python34.dll;	To be installed;	Won't patch;	No existing file
MSI (s) (48:2C) [01:28:13:007]: Source for file 'python34.dll' is compressed
InstallFiles: File: python34.dll,  Directory: C:\Windows\system32\,  Size: 4044800



BUT!  python34.dll not in C:\Windows\system32\ folder and not in C:\Windows\SysWOW64\ folder. :(

I just installed 64-bit 3.4.0 on 64-bit Win7 with no trouble at all, and python34.dll is sitting happily in C:\Windows\System32.

To try to figure out what you did that I didn't (or vice versa), I have a few questions for you:

1) How did you run the installer?

2) Did you choose to install "for all users" or "just for me"?

3) Did you run the installer with administrative privileges, or did it ask for elevation of privileges?

4) Did you select/unselect any options such that they did not match default (default being all options will be installed, except adding python.exe to PATH)?

For my successful install, I 1) ran the installer by the classic double-click-the-icon method, 2) installed for all users, 3) gave elevated privileges when it asked, and 4) left all options at default.

>For my successful install, I 1) ran the installer by the classic double-click-the-icon method, 2) installed for all users, 3) gave elevated privileges when it asked, and 4) left all options at default.

Yes. And I did so.

This is a very strange problem.
I tried to install on another PC and everything is normal. X86 version on my machine so the same set perfectly. But the version of x86-64 does not install python34.dll on my machine.

I tried to reboot, unloaded many active processes, disable Anti-Virus - nothing helps.
I understand that the problem is on my PC, I will try next.

I noticed that after installing the file python34.dll belongs to the owner of the "system". While the other files in the system32 folder belonging to the owner of the "TrustedInstaller".
Possibly this is a problem. My file manager just does not display the file, although running with administrator privileges.

If it possible, make sure that the installation packages are customized to create files with a really correct owners and permissions on the file python34.dll.

Mikhail: I'm not sure whether there is a problem left to be resolved. The installer log file clearly says that python34.dll was installed to system32, and your last message indicates that the file is actually present, as it should.

The ownership is not a problem. TrustedInstaller is used to install files that come with Windows itself, including updates, services packs and the like. Third-party software (such as Python) is not managed by the TrustedInstaller.

Yes. I agree. Closed. 
Sorry for the panic :)