`Warning: The post-install step did not complete successfully` for all packages

[bfallik-invaluable]

brew config AND brew doctor output OR brew gist-logs <formula> link

❯ brew config
HOMEBREW_VERSION: 5.1.13
ORIGIN: https://github.com/Homebrew/brew
HEAD: d8deaca5574faf79a27f110caedc9e153709e628
Last commit: 11 hours ago
Branch: stable
Core tap JSON: 22 May 02:27 UTC
Core cask tap JSON: 22 May 02:27 UTC
HOMEBREW_PREFIX: /opt/homebrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_DOWNLOAD_CONCURRENCY: 24
HOMEBREW_EDITOR: nano
HOMEBREW_FORBID_PACKAGES_FROM_PATHS: set
HOMEBREW_MAKE_JOBS: 12
Homebrew Ruby: 4.0.5 => /opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/bin/ruby
CPU: dodeca-core 64-bit arm_blizzard_avalanche
Clang: 17.0.0 build 1700
Git: 2.54.0 => /opt/homebrew/bin/git
Curl: 8.7.1 => /usr/bin/curl
macOS: 26.3.1-arm64
CLT: 26.3.0.0.1.1771626560
Xcode: N/A
Rosetta 2: false

❯ brew doctor
Your system is ready to brew.

Verification

• My brew doctor output says Your system is ready to brew. and am still able to reproduce my issue.
• I ran brew update and am still able to reproduce my issue.
• I have resolved all warnings from brew doctor and that did not fix my problem.
• I searched for recent similar issues at https://github.com/Homebrew/homebrew-core/issues?q=is%3Aissue and found no duplicates.
• My issue is not about a failure to build a formula from source.

What were you trying to do (and why)?

Trying to install any new package and received WARNING that postinstall failed. This happens for any package I install or reinstall using brew.

What happened (include all command output)?

Here's a basic repro with jq:

 brew reinstall jq
==> Fetching downloads for: jq
✔︎ Bottle Manifest jq (1.8.1)                         Downloaded   10.8KB/ 10.8KB
✔︎ Bottle jq (1.8.1)                                  Downloaded  424.2KB/424.2KB
==> Reinstalling jq
==> Pouring jq--1.8.1.arm64_tahoe.bottle.tar.gz
Warning: The post-install step did not complete successfully
You can try again using:
  brew postinstall jq
==> Summary
🍺  /opt/homebrew/Cellar/jq/1.8.1: 20 files, 1.2MB
==> Running `brew cleanup jq`...
Disable this behaviour by setting `HOMEBREW_NO_INSTALL_CLEANUP=1`.
Hide these hints with `HOMEBREW_NO_ENV_HINTS=1` (see `man brew`).

And more details if I call postinstall directly:

❯ brew postinstall -v --debug jq
/opt/homebrew/Library/Homebrew/brew.rb (Formulary::FromAPILoader): loading jq
/opt/homebrew/Library/Homebrew/brew.rb (Formulary::FromAPILoader): loading homebrew/core/jq
==> Postinstalling jq
Warning: The post-install step did not complete successfully
You can try again using:
  brew postinstall jq
==> Failure while executing; `/usr/bin/sandbox-exec -f /private/tmp/homebrew-sandbox20260521-96407-u2i3i5/homebrew.sb nice /opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/bin/ruby -W1 --disable=gems,rubyopt -I /opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/bundler-4.0.10/lib:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/gems/4.0.0/gems/reline-0.6.3/lib:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/gems/4.0.0/gems/rdoc-7.0.4/lib:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/gems/4.0.0/gems/rake-13.3.1/lib:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/gems/4.0.0/gems/msgpack-1.8.0/lib:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/gems/4.0.0/gems/irb-1.16.0/lib:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/gems/4.0.0/gems/fiddle-1.1.8/lib:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/gems/4.0.0/gems/debug-1.11.1/lib:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/gems/4.0.0/gems/bootsnap-1.24.4/lib:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/gems/4.0.0/extensions/arm64-darwin-20/4.0.0-static/msgpack-1.8.0:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/gems/4.0.0/extensions/arm64-darwin-20/4.0.0-static/fiddle-1.1.8:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/gems/4.0.0/extensions/arm64-darwin-20/4.0.0-static/debug-1.11.1:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/gems/4.0.0/extensions/arm64-darwin-20/4.0.0-static/bootsnap-1.24.4:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/yard-sorbet-0.9.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/yard-0.9.43/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/warning-1.5.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/vernier-1.10.1/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/extensions/arm64-darwin-20/4.0.0-static/vernier-1.10.1:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/test-prof-1.6.1/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/tapioca-0.19.1/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/stackprof-0.2.28/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/extensions/arm64-darwin-20/4.0.0-static/stackprof-0.2.28:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/spoom-1.7.14/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/thor-1.5.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/sorbet-static-and-runtime-0.6.13201/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/sorbet-0.6.13201/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/sorbet-static-0.6.13201-universal-darwin/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/simplecov-cobertura-3.1.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/simplecov-0.22.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/simplecov_json_formatter-0.1.4/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/simplecov-html-0.13.2/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rubydex-0.2.1-arm64-darwin/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/ruby-prof-2.0.4/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/extensions/arm64-darwin-20/4.0.0-static/ruby-prof-2.0.4:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/ruby-macho-5.0.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/ruby-lsp-0.26.9/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rubocop-sorbet-0.12.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rubocop-rspec-3.9.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rubocop-performance-1.26.1/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rubocop-md-2.0.4/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rubocop-1.86.1/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/unicode-display_width-3.2.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/unicode-emoji-4.2.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/ruby-progressbar-1.13.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rubocop-ast-1.49.1/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rspec_junit_formatter-0.6.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rspec-sorbet-1.9.2/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/sorbet-runtime-0.6.13201/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rspec-retry-0.6.2/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rspec-github-3.0.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rspec-3.13.2/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rspec-mocks-3.13.8/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rspec-expectations-3.13.5/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rspec-core-3.13.6/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rspec-support-3.13.7/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/require-hooks-0.4.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/redcarpet-3.6.1/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/extensions/arm64-darwin-20/4.0.0-static/redcarpet-3.6.1:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rbi-0.3.11/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rbs-4.0.2/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/extensions/arm64-darwin-20/4.0.0-static/rbs-4.0.2:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/tsort-0.2.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rainbow-3.1.1/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/pycall-1.5.2/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/extensions/arm64-darwin-20/4.0.0-static/pycall-1.5.2:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/pry-0.16.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/reline-0.6.3/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/plist-3.7.2/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/patchelf-1.5.2/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/parser-3.3.11.1/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/racc-1.8.1/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/extensions/arm64-darwin-20/4.0.0-static/racc-1.8.1:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/parallel_tests-5.7.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/parallel-2.1.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/ostruct-0.6.3/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/netrc-0.11.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/minitest-6.0.6/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/prism-1.9.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/extensions/arm64-darwin-20/4.0.0-static/prism-1.9.0:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/method_source-1.1.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/logger-1.7.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/lint_roller-1.1.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/language_server-protocol-3.17.0.5/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/kramdown-2.5.2/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/rexml-3.4.4/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/json_schemer-2.5.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/simpleidn-0.2.3/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/regexp_parser-2.12.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/json-2.19.5/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/extensions/arm64-darwin-20/4.0.0-static/json-2.19.5:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/io-console-0.8.2/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/extensions/arm64-darwin-20/4.0.0-static/io-console-0.8.2:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/hana-1.3.7/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/erubi-1.13.1/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/elftools-1.3.1/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/drb-2.2.3/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/docile-1.4.1/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/diff-lcs-1.6.2/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/csv-3.3.5/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/concurrent-ruby-1.3.6/lib/concurrent-ruby:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/coderay-1.1.3/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/bindata-2.5.1/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/bigdecimal-4.1.2/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/extensions/arm64-darwin-20/4.0.0-static/bigdecimal-4.1.2:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/benchmark-0.5.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/base64-0.3.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/ast-2.4.3/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/addressable-2.9.0/lib:/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/public_suffix-7.0.5/lib:/opt/homebrew/Library/Homebrew:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/vendor_ruby/4.0.0:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/vendor_ruby/4.0.0/arm64-darwin20:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/vendor_ruby:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/4.0.0:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/4.0.0/arm64-darwin20 -- /opt/homebrew/Library/Homebrew/postinstall.rb /opt/homebrew/opt/jq/.brew/jq.rb` was terminated by uncaught signal KILL.
/opt/homebrew/Library/Homebrew/sandbox.rb:329:in 'block (3 levels) in Sandbox#run'
/opt/homebrew/Library/Homebrew/sandbox.rb:345:in 'IO#raw'
/opt/homebrew/Library/Homebrew/sandbox.rb:345:in 'block (2 levels) in Sandbox#run'
/opt/homebrew/Library/Homebrew/sandbox.rb:280:in 'PTY.open'
/opt/homebrew/Library/Homebrew/sandbox.rb:280:in 'block in Sandbox#run'
/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5/lib/ruby/4.0.0/tmpdir.rb:105:in 'Dir.mktmpdir'
/opt/homebrew/Library/Homebrew/sandbox.rb:273:in 'Sandbox#run'
/opt/homebrew/Library/Homebrew/formula_installer.rb:1377:in 'FormulaInstaller#post_install'
/opt/homebrew/Library/Homebrew/cmd/postinstall.rb:25:in 'block in Homebrew::Cmd::Postinstall#run'
/opt/homebrew/Library/Homebrew/cmd/postinstall.rb:20:in 'Array#each'
/opt/homebrew/Library/Homebrew/cmd/postinstall.rb:20:in 'Homebrew::Cmd::Postinstall#run'
/opt/homebrew/Library/Homebrew/brew.rb:114:in '<main>'

What did you expect to happen?

No warnings about postinstall failure.

Step-by-step reproduction instructions (by running brew commands)

`brew install jq`

[p-linnane]

jq doesn't even have a post_install block:

╰─ brew postinstall -dv jq
/opt/homebrew/Library/Homebrew/brew.rb (Formulary::FromNameLoader): loading jq
/opt/homebrew/Library/Homebrew/brew.rb (Formulary::FromNameLoader): loading jq
/opt/homebrew/Library/Homebrew/brew.rb (Formulary::FromNameLoader): loading jq
==> Postinstalling jq
Warning: jq: no `post_install` method was defined in the formula!

Is this a corporate machine with MDM/EDR on it? Something is killing Ruby.

[bfallik-invaluable]

@p-linnane yes, this is a company laptop but there shouldn't be anything like that installed on it. (I manage our IT team and am familiar with everything that we install to support our corporate IT policy)

Any ideas how I can debug this further?

[Bo98]

So there's two issues here:

1. brew postinstall shouldn't need to be run on jq at all when doing brew install. This is a bug our side which we'll fix: api: fix every formula having a post install defined brew#22378
2. brew postinstall, regardless whether it is necessary or not, should not fail with SIGKILL. This is probably an issue on your side given you are the only person to have reported this. I'm not entirely sure what the issue may be but Console.app (or the equivalent log CLI) will very likely output something that explains why. Not entirely sure what to search but keywords like brew, ruby or sandbox might help narrow down the logs enough.

[p-linnane]

After hitting the failure, try
log show --predicate 'sender == "sandboxd" OR sender == "kernel"' --last 2m | grep -iE 'deny|kill|ruby'