nix_update_issue.sh

#!/bin/bash

# Issue: This occurs when updating OSX.

# It seems the build group nixbld already exists, but
# with the UID 30000. This script can't really handle
# that right now, so I'm going to give up.

# You can export NIX_BUILD_GROUP_ID=30000 and re-run.
# However setting this will not fix this error. Remove the users and groups

set -euo pipefail

for i in {1..32}; do
  echo "Removing nixbld$i" 
  sudo dscl . delete /Users/_nixbld$i
done

sudo dscl . delete /Groups/nixbld