There is a small bug in the activate.bat script causing problems on internationalized Windows systems.

C:\repo\gui>python -m venv venv

C:\repo\gui>call venv\Scripts\activate.bat
Parameterformat falsch - 850.

This translates to "Wrong parameter - 850."

For the user it is not obvious what went wrong. 

The virtual environment is setup and will work in most cases.

Link to https://bugs.python.org/issue32409.

So - are you saying that chcp prints "850." when asked for the current code page but won't accept "850." when setting the code page, requiring just "850"?

The Windows command line often has inconsistently localized strings. In this case it's from the ulib.dll utility library. For German, message 0x7692 in "de-DE\ulib.dll.mui" is "Aktive Codepage: %1.\r\n", which has a period after the %1 insert. In the English UI it's "Active code page: %1\r\n", with no period. I commented on the PR that we could work around this by adding "." to the list of token delimiters (delims).

Fixed, see bpo-32409 for commit information.

Dear developers on the nosy list: Would it be possible that someone does a quick review of my related fix in https://github.com/python/cpython/pull/10696?

It is extremely simple and has minimal side effects, but would relieve us from getting this annoying error in the future.

I know this is a minor thing but each time I start a venv in Germany, I am reminded of this... :-)

Thanks a lot.