Karls-Mac-mini:~ karl$ perlbrew install --as perl-5.30.3-threads -Dusethreads perl-5.30.3 Installing /Users/karl/perl5/perlbrew/build/perl-5.30.3/perl-5.30.3 into ~/perl5/perlbrew/perls/perl-5.30.3-threads This could take a while. You can run the following command on another shell to track the status: tail -f ~/perl5/perlbrew/build.perl-5.30.3.log Installation process failed. To spot any issues, check /Users/peter/perl5/perlbrew/build.perl-5.30.3.log If some perl tests failed and you still want to install this distribution anyway, do: (cd /Users/karl/perl5/perlbrew/build/perl-5.30.3/perl-5.30.3; make install) You might also want to try upgrading patchperl before trying again: perlbrew install-patchperl Generally, if you need to install a perl distribution known to have minor test failures, do one of these commands to avoid seeing this message: perlbrew --notest install perl-5.30.3 perlbrew --force install perl-5.30.3