Install root on mac M1


I was trying to install root on a new mac M1, either with brew or macports, but the installation fails in both cases[*]. Is there any recipe for that?


Error: Cannot install in Homebrew on ARM processor in Intel default prefix (/usr/local)!
Please create a new installation in /opt/homebrew using one of the
"Alternative Installs" from:
You can migrate your previously installed formula list with:
  brew bundle dump

> sudo port install root6
Error: Current platform "darwin 21" does not match expected platform "darwin 16"
Error: If you upgraded your OS, please follow the migration instructions:
OS platform mismatch
    while executing
"mportinit ui_options global_options global_variations"
Error: /opt/local/bin/port: Failed to initialize MacPorts, OS platform mismatch

I am not sure what wrong with these pre-installed version. Have you search on this forum ?
I do not have expertise with HomeBrew nor macports. I usually install from sources.

Just to give some more help, I am under Monterey 12.2.1 - I found a relevant thread ROOT 6.24/06 can not work on macOS Monterey but it does not help me, as I always fail building from the source @couet what the recommendation is for Monterey? build from conda/brew?

For the brew errors, maybe @henryiii has an idea.

Otherwise you can follow the instructions at Installing ROOT - ROOT, @Axel can correct me if I’m wrong but the binaries for v6.26 should support M1.


Homebrew should be updated soon, I’m just stuck on the formula segfaulting on linuxbrew (works fine on homebrew macOS). Conda just got updated as well.

It looks like you are trying to install Intel Homewbrew on ARM - you need to use ARM homebrew, which installs to /opt/homebrew instead of /usr/local.

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And yes we have binaries; those labeled “ARM” are for M1.

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hi @Axel - I have just tried via brew brew install root it still downloads the 6.24.06.source and then when it tries to compile I get an error about fortran not existing, which is not true

I was referring to the binaries offered on For brew, @henryiii is the authoritative source of information.

ok, quick update - I totally deleted brew and reinstalled it - After that, I could install root from brew with no problems!


You should be able to upgrade to 6.26 now too. :slight_smile: I expect you installed brew quite a while ago or you installed it in a Rosetta shell, causing you to get the Intel version instead of the ARM one. It should work correctly in the ARM version.

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