Why does conda try to update packages with --no-update-dependencies?

tldr;

Don't worry about it, your packages are not being updated, only their build numbers, which should be harmless.

some explanation

What is being updated is the build number, not the version of each package installed.

As you can see, it is installing the vs2010_runtime, this is due to conda updating how its packages were built using features. Since you have Python 3.4 (which is built using Visual Studio 2010) it is installing the VS 2010 runtime. It would install the VS 2015 runtime if you were installing Python 3.5.

Build numbers/strings shouldn't break anyone because they're supposed to be fixes to the build process of that package (eg: you added a flag to the compilation which you didn't intend to).

It is arguable if conda should update the packages (same version, different build numbers) when --no-update-dependencies is present because you might end up with a bad installation.

Just want to mention that these options are deprecated in new conda versions. For example, in conda version 4.6.7, you should use "conda install --no-deps yourpackage"