Martin, while I technically understand your anwers, I have to say that from an ordinary developer's perspective, the behavior is actually *not* expected.

It may be expected for python-dev experts, but not for those who are just programming _with_ python.

It did cost me half a day to find out what's going on. Luckily, this happened on an internal development machine and not while installing the application on one of our customer's machine.

IIRC earlier versions of python did not install a python2*.* ZIP or DLL into %WINDIR%\System32.

It should at least be documented that installing two different 2.7.x releases on the same machine is not supported.

Furthermore, the technical difference between "install for all users" and "install just for me" is not clear.

As you said, the docs do not even mention that after an installation "for all users" the system uses %WINDIR%\System32\python2x.zip for searching libraries.

For a developer it is not obvious that hmac is built in while other standard libs (implemented in pure Python) are not.

BTW, if it was built-in (technically), then it could not be not found, as it happened to Andreas and me.
Fool-proof built-in would mean: statically linked with the executable, not in a DLL.

I recommend to keep things as is, but add a few sentences to the docs.