CondaUpgradeError: This environment has previously been operated on by a conda version that's newer

Question

I was trying to fix an issue with an old environment earlier today and screwed up conda . I get this:

Solving environment: failed

CondaUpgradeError: This environment has previously been operated on by a conda version that's newer
than the conda currently being used. A newer version of conda is required.
  target environment location: /Users/U6020643/anaconda3
  current conda version: 4.5.11
  minimum conda version: 4.8

The original problem: I recently upgraded to Catalina, and could not build Pandas when installing it to recreate an environment.

Rehoming: Was this post regarding How to Restore Anaconda after Update to MacOS Catalina . I downloaded the script and ran it. It appeared to work. But I had the same problem with Pandas.

./cpr rehome ~/anaconda3

Installing a revision : At some point in my debugging I also ran this, which I have a hunch caused the problem.

conda install --revision 0

Trying to install Conda 4.8 : I found this post and attempted the accepted solution.

I added allow_conda_downgrades: true to my ~/.condarc file. conda update conda produced the same CondaUpgradeError and so did conda install conda==4.8.1 .

Next I found the package-cache via conda info and attempted to install 4.8 from there. Here is my conda info output.

     active environment : None
       user config file : /Users/me/.condarc
 populated config files : /Users/me/.condarc
          conda version : 4.5.11
    conda-build version : 3.15.1
         python version : 3.7.0.final.0
       base environment : /Users/me/anaconda3  (writable)
           channel URLs : https://repo.anaconda.com/pkgs/main/osx-64
                          https://repo.anaconda.com/pkgs/main/noarch
                          https://repo.anaconda.com/pkgs/free/osx-64
                          https://repo.anaconda.com/pkgs/free/noarch
                          https://repo.anaconda.com/pkgs/r/osx-64
                          https://repo.anaconda.com/pkgs/r/noarch
                          https://repo.anaconda.com/pkgs/pro/osx-64
                          https://repo.anaconda.com/pkgs/pro/noarch
          package cache : /Users/me/anaconda3/pkgs
                          /Users/me/.conda/pkgs
       envs directories : /Users/me/anaconda3/envs
                          /Users/me/.conda/envs
               platform : osx-64
             user-agent : conda/4.5.11 requests/2.19.1 CPython/3.7.0 Darwin/19.6.0 OSX/10.15.6
                UID:GID : 502:20
             netrc file : None
           offline mode : False

Then I downloaded osx-64/conda-4.8.3-py37_0.tar.bz2 from Anaconda here , put it into /Users/me/anaconda3/pkgs/ , and tried:

conda install /Users/me/anaconda3/pkgs/conda-4.8.3-py37_0.tar.bz2

Which resulted in this issue, where I continue to be stuck.

Preparing transaction: done
Verifying transaction: failed

RemoveError: 'conda-package-handling' is a dependency of conda and cannot be removed from
conda's operating environment.

Before marking as duplicate: consider carefully the similar posts. The version numbers here are different, the path and circumstances that resulted in this problem are different, and I have attempted those solutions without luck.

Answer 1

Standalone Conda

I would try downloading a standalone version of Conda that matches the old version of Conda you had (something in v4.8.x), and then try using this to upgrade the Conda package in the base env.

I don't know for sure this will work, but it is pretty simple and will not change anything unless it does work.

Downloads

You can download builds of conda-standalone (PyInstaller-based binaries) from either the Anaconda or Conda Forge channel. Browse to your version (or something close), download the archive (to wherever), unzip, and in the folder standalone_conda you will find a conda.exe file, which is the binary you'll need.

Configuration

Next, you need to set the environment variable CONDA_ROOT_PREFIX to point to your base env's folder, which from your output is /Users/me/anaconda3/ . So,

export CONDA_ROOT_PREFIX=/Users/me/anaconda3

Then, to test, check

./conda.exe info

and verify that the values for base environment: , package cache: , and envs directories point to the correct locations, which in a default install would be /Users/me/anaconda3 , /Users/me/anaconda3/pkgs , and /Users/me/anaconda3/envs , respectively.

Upgrade

Attempt upgrading the conda package in the base env:

./conda.exe upgrade -n base -c defaults conda

Hopefully, the error you reported before doesn't recur, but I'm actually not sure. Make sure to review any changes if the solve does work.

In the end you can discard the conda.exe and go back to using the one in base .