# Error starting dev stack on Mac OS
**URL:** https://discuss.openedx.org/t/error-starting-dev-stack-on-mac-os/2833
**Category:** Site Operations Help
**Created:** [July 28, 2020, 5:28am UTC](https://discuss.openedx.org/t/error-starting-dev-stack-on-mac-os/2833 "2020-07-28T05:28:48Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@victorleungtw](https://discuss.openedx.org/u/victorleungtw)
#### Post date: [July 28, 2020, 5:28am UTC](https://discuss.openedx.org/t/error-starting-dev-stack-on-mac-os/2833/1 "2020-07-28T05:28:48Z")
Following the readme in [https://github.com/edx/devstack](https://github.com/edx/devstack),
After executing the command “make dev.provision”, I hit the error:
Starting edx.devstack.studio … done
++ docker-compose exec -T lms bash -c ‘source /edx/app/edxapp/edxapp\_env && cd /edx/app/edxapp/edx-platform && NO\_PYTHON\_UNINSTALL=1 paver install\_prereqs’
Build failed: Unknown task: install\_prereqs
make: \*\*\* [dev.provision] Error 1
May I know if it’s something wrong with paver task? Thank you.
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### Author:  [@guruprasad](https://discuss.openedx.org/u/guruprasad)
#### Post date: [August 24, 2020, 7:18am UTC](https://discuss.openedx.org/t/error-starting-dev-stack-on-mac-os/2833/2 "2020-08-24T07:18:41Z")
@victorleungtw, the `install_prereqs` sub-command is built into `paver` and should run without any issues. When following the steps in the [edx/devstack](https://github.com/edx/devstack) repository, did you notice any errors in any of the steps before? Also, did you follow all the steps specific to macOS documented in the `README` file of this repository?
To investigate your issue further, it will be helpful if you can provide more details about the Open edX release that you are trying to run in the devstack - is it the `master` branch or is it a named release like Juniper, Ironwood etc. and if there are any quirks in your setup?
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### Author:  [@sergio-neosoltec](https://discuss.openedx.org/u/sergio-neosoltec)
#### Post date: [November 5, 2020, 6:31pm UTC](https://discuss.openedx.org/t/error-starting-dev-stack-on-mac-os/2833/3 "2020-11-05T18:31:22Z")
I had the same problem. I solved it by making sure python3 was the version available in the environment variables.