MACHINE=foo is invalid. Please set a valid MACHINE in your local.conf

When starting my build, I get:

ERROR:  OE-core's config sanity checker detected a potential misconfiguration.
    Either fix the cause of this error or at your own risk disable the checker (see sanity.conf).
    Following is the list of potential problems / advisories:

    MACHINE=foo is invalid. Please set a valid MACHINE in your local.conf, environment or other configuration file.

Inside build/conf/local.conf file, I tell bitbake to build that machine:

MACHINE = 'foo'

Online search did not return useful results for me.

Solution

Make sure the machine name foo in your local.conf is correct.

Also make sure that there is a valid configuration for that machine in some meta layer. I.e. search for a conf/machine/foo.conf file in all meta-foobar directories.

find . -wholename "*conf/machine*" | grep foo  # Remove grep to see all MACHINEs