Hi, Starting Tuesday several contributors to StarlingX docs can no longer successfully perform local doc builds: $ tox -e docs docs installed: alabaster==0.7.12,Babel==2.9.0,certifi==2020.11.8,chardet==3.0.4,colorama==0.4.4,docutils==0.15.2,dulwich==0.20.14,idna==2.10,imagesize==1.2.0,Jinja2==2.11.2,MarkupSafe==1.1.1,openstackdocstheme==2.2.7,os-api-ref==2.1.0,packaging==20.7,pbr==5.5.1,Pygments==2.7.2,pyparsing==2.4.7,pytz==2020.4,PyYAML==5.3.1,requests==2.25.0,six==1.15.0,snowballstemmer==2.0.0,Sphinx==3.3.1,sphinxcontrib-applehelp==1.0.2,sphinxcontrib-devhelp==1.0.2,sphinxcontrib-htmlhelp==1.0.3,sphinxcontrib-jsmath==1.0.1,sphinxcontrib-qthelp==1.0.3,sphinxcontrib-serializinghtml==1.1.4,urllib3==1.26.2 docs run-test-pre: PYTHONHASHSEED='662' docs run-test: commands[0] | sphinx-build -a -E -W -d doc/build/doctrees -b html doc/source doc/build/html ERROR: InvocationError for command could not find executable sphinx-build ___________________________________ summary ___________________________________ ERROR: docs: commands failed The executable sphinx-build.exe is missing from docs/.tox/docs/Scripts/ If manually restored, it is deleted the next time tox -e docs is run. Deleting .tox before rerunning does not help. Wondering if anyone is seeing this behavior with OpenStack docs and if it might be related to recent pip and virtualenv changes. Ron