Brew installation of ROOT problem with python

ROOT Version: 6.26.06_2
Platform: Mac OS Monterey 12.6.3 (Intel)
Compiler: Apple clang version 14.0.0 (clang-1400.0.29.202)

The brew website for root (*) says that the “stable” version of root is 6.26.06 and that it needs python 3.10.10

I just installed with “brew install root” and I do indeed use python 3.10.10.
However, when I try to “import ROOT” it claims that the python version is wrong (see below)




(*) Sorry, I would post a link but I am not allowed.
$ python3
Python 3.10.10 (main, Feb 16 2023, 02:58:25) [Clang 14.0.0 (clang-1400.0.29.202)] on darwin
Type “help”, “copyright”, “credits” or “license” for more information.

import ROOT as r
Traceback (most recent call last):
File “”, line 1, in
File “/usr/local/Cellar/root/6.26.06_2/lib/root/ROOT/”, line 22, in
import cppyy
File “/usr/local/Cellar/root/6.26.06_2/lib/root/cppyy/”, line 96, in
ver = _check_py_version(lib_name[start:], cbl_var)
File “/usr/local/Cellar/root/6.26.06_2/lib/root/cppyy/”, line 77, in _check_py_version
raise RuntimeError(‘CPPYY_BACKEND_LIBRARY variable ({})’
RuntimeError: CPPYY_BACKEND_LIBRARY variable (/usr/local/Cellar/root/6.24.06/lib/root/ does not match Python version 3.10

Problem solved, sorry for the noise.
I had the CPPYY_BACKEND_LIBRARY env variable pointing to an older version of root.

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