Multiple Versions of Python on Windows XP

Colin J. Williams cjw at
Tue Dec 2 20:50:03 CET 2008

Martin v. Löwis wrote:
>> Could anyone please point me to documentation on the way the msi
>> installer handles multiple versions eg. Python 2.5, 2.6 and 3.0?
> I don't think that is documented anywhere.
>> What changes are made to the registry?
> For a complete list, see Tools/msi/ in the source tree.

I have scanned the file:

I don't find anything that addresses 
this issue.

>> Is there some way to specify a default version in such a way that it can
>> be changed as necessary?
> What do you mean by "default version"?

I am seeking some mechanism such that 
any of Python 2.5, Python 2.6 or Python 
2.6 can be chosen as the currently 
active version.

> There is the version that is associated with the .py/.pyc extensions
> at any point in time; you can change these by re-running the respective
> installers from add-and-remove-programs. In a well-managed installation,
> only one Python installation would have the "Register Extensions"
> feature selected; to then change the default, one would unselect the
> feature in one version, and reselect it in a different. If only the
> default installation procedure was ever used, re-running the installer
> in "Repair" mode (from ARP) will also restore the extension
> associations.

I was hoping that there is some simpler 
way than the "Repair" procedure.

>> PyScripter uses an option to select a version eg.
>> C:\Program Files\PyScripter\PyScripter.exe --python26
>> but I'm having some trouble with it when I attempt edit a python file
>> from the Windows Explorer.
> It would be good to be more specific with such statements: what troubles
> specifically? If I play dumb, I'd say "of course - windows explorer
> doesn't support editing Python files; you need a text editor".

Yes, I should have been clearer.  The 
PyScripter application locks up and must 
be killed, using the Task Manager.

Many thanks for your response.

Best wishes,

Colin W.
> Regards,
> Martin

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