Encountering fatal error x80070643 while installing Python

[eryk sun]

On Fri, Nov 18, 2016 at 5:55 PM, MRAB <python at mrabarnett.plus.com> wrote:
> On 2016-11-18 11:40, Irene Venditti wrote:
>>
>> This didn't seem to be a problem, since version 3.5.1 installed to my
>> C:\Users\username\appdata\local\... directory. But when I tried to install
>> Python 3.5.2 and uninstalled both previous versions, the problems began.
>>
>> Now I cannot install any version of Python anymore, not 3.5.0 or any later
>> versions. At the end of the procedure I get a fatal error message, with
>> code 0x80070643, saying an error was encountered and the installation
>> couldn't be completed.
>
> Have you tried manually deleting those folders? You could just rename them
> instead and delay deleting them until the problem is fixed.
>
> It's recommended to give the Python folder a name that reflects its version,
> e.g. Python35. If you want both the 64-bit and 32-bit versions, then
> Python35-32 and Python35 (or Python35-64).

It looks like the OP is using the default per-user target directory,
"%LocalAppData%\Programs\Python\Python35[-32]". It's possible
something was left there by the old 3.5.1 installation, such as
pip/setuptools in site-packages, which is causing the 3.5.2
installation to fail. I would first try the "repair" option using the
3.5.1 installer, if that's an available option. Then upgrade to 3.5.2.
You shouldn't need to remove 3.5.1 to install 3.5.2. It's an in-place
upgrade.