About two years ago I moved from pip to conda. I have been happy with
conda until yesterday.

I want to create a new environment using a specific python version
rather than leaving that to conda. Cheat-sheets and online conda
documentation tell me to use:

conda create -n <name> python=<version number>

like:

conda create -n test python=3.10

Which in my case yields an error message saying python 3.10 is not
available in this environment.

I have tried variations on the python specification:

python==3.10.12
python=3.10.12

To no avail.

I think (!??!) I have managed to do this in the past.

Any help is more than welcome.

/Martin

--- PyGate Linux v1.5
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Hi Martin,

Martin Sch””n <martin.schoon@gmail.com> writes:

About two years ago I moved from pip to conda. I have been happy with
conda until yesterday.

I want to create a new environment using a specific python version
rather than leaving that to conda. Cheat-sheets and online conda documentation tell me to use:

conda create -n <name> python=<version number>

like:

conda create -n test python=3.10

Which in my case yields an error message saying python 3.10 is not
available in this environment.

I have tried variations on the python specification:

python==3.10.12
python=3.10.12

To no avail.

I think (!??!) I have managed to do this in the past.

Any help is more than welcome.

/Martin

If I use an environment which provides Python 3.12 I can run both

conda create -n test python=3.10

and

conda create -n test python=3.14

I only get the error

PackagesNotFoundError: The following packages are not available from current channels:

if I do something I would expect to fail, like

conda create -n test python=3.99

Do you see a line such as

Collecting package metadata (repodata.json): done

If not, maybe your repodata.json is not getting updated and the current
one does not contain the Python version you are requesting.

Regards

Loris

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--- PyGate Linux v1.5
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Den 2025-11-13 skrev Loris Bennett <loris.bennett@fu-berlin.de>:
Hi Loris,

Thanks for quick respons.

Martin Sch””n <martin.schoon@gmail.com> writes:

I want to create a new environment using a specific python version
rather than leaving that to conda. Cheat-sheets and online conda
documentation tell me to use:

conda create -n <name> python=<version number>

like:

conda create -n test python=3.10

Which in my case yields an error message saying python 3.10 is not
available in this environment.

I have tried variations on the python specification:

python==3.10.12
python=3.10.12

To no avail.

If I use an environment which provides Python 3.12 I can run both

conda create -n test python=3.10

and

conda create -n test python=3.14

I only get the error

PackagesNotFoundError: The following packages are not available from current channels:

if I do something I would expect to fail, like

conda create -n test python=3.99

Do you see a line such as

Collecting package metadata (repodata.json): done

If not, maybe your repodata.json is not getting updated and the current
one does not contain the Python version you are requesting.

Regards

Loris

I have now run a series of tests on my main system running Debian 12 and
in a virtual machine updated to Debian 13. I get the same result in both
cases.

If I don't specify a python version all is fine.

If I try to specify a python version I don't get a new environment. The
error message I get is:

"The following packages are missing from the target environment:

- python=3.10"

(if I asked for version 3.10)

Some observations:

Myself, I can't find repodata.json. Not in my user directories at
least. Conda reports it can collect metadata anyway.

The main system has base python version 3.12.12 and the environment I
get if I don't specify a python version is equipped with version 3.11.2

In the virtual machine the base python is 3.11.5 and the created
environment gets 3.13.5

The last two ones look odd to me but that is what python3 --version
yields.

/Martin

--- PyGate Linux v1.5
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

Den 2025-11-14 skrev Stefan Ram <ram@zedat.fu-berlin.de>:

Martin =?UTF-8?Q?Sch=C3=B6=C3=B6n?= <martin.schoon@gmail.com> wrote or quoted:

If I try to specify a python version I don't get a new environment. The >>error message I get is:
"The following packages are missing from the target environment:
- python=3.10"
(if I asked for version 3.10)

I'm not educated in Conda. But here are some wild and untested
guesses what could be done:

Your conda know-how is most likely superior to mine :-)

conda search python

This might list the Python versions available.

Yields an error message very similar to the one cited above.

If the desired version does not appear, adding a channel known
to host older versions might help, like:

conda create -n test python=3.10 -c conda-forge

Bingo! This works for me.

. It might help to update Conda:

conda update conda

Was already up-to-date.

Didn't bother testing the following. Later maybe.

. This should clear the Conda cache, but I don't know what you might
lose by doing it:

conda clean --all

. Check out your conda base and user PATH variables, and prioritize
Conda environments over system-wide Python installations.

Check your system's networking/firewall configuration doesn't block
Conda's access to remote repositories.

You could also try to require a more specific version you have,
like for example, "python=3.10.4", instead of, "python=3.10".

Many thanks.

/Martin

--- PyGate Linux v1.5
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)