06.2026: "brew update" gives error "Error: can't modify frozen Array: []"

Quotenfrau · Friday at 8:02 PM

Hi

Code:

brew update
==> Updating Homebrew...
Already up-to-date.
Error: can't modify frozen Array: []

How-To fix?

Bigwaff · Friday at 8:58 PM

You have a broken third-party tap. Run brew doctor in verbose mode to discover which tap. Remove tap.

Quotenfrau · Friday at 9:06 PM

Code:

brew doctor
Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry or file an issue; just ignore this. Thanks!

Warning: Some installed formulae are deprecated or disabled.
You should find replacements for the following formulae:
  mdcat

No issues with taps

Code:

brew doctor -v
==> Cask Environment Variables:
HOMEBREW_CASK_OPTS="--appdir\=/Users/john/Applications"
LC_ALL="en_US.UTF-8"
PATH="/opt/homebrew/Library/Homebrew/shims/shared:/usr/bin:/bin:/usr/sbin:/sbin"
SHELL="/bin/zsh"
==> $LOAD_PATHS
/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_1/lib/ruby/gems/4.0.0/gems/reline-0.6.3/lib
/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5_1/lib/ruby/gems/4.0.0/gems/rdoc-7.0.4/lib
/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5_1/lib/ruby/gems/4.0.0/gems/rake-13.3.1/lib
/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5_1/lib/ruby/gems/4.0.0/gems/msgpack-1.8.0/lib
/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5_1/lib/ruby/gems/4.0.0/gems/irb-1.16.0/lib
/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5_1/lib/ruby/gems/4.0.0/gems/fiddle-1.1.8/lib
/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5_1/lib/ruby/gems/4.0.0/gems/debug-1.11.1/lib
/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5_1/lib/ruby/gems/4.0.0/gems/bootsnap-1.24.5/lib
/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5_1/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_1/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_1/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_1/lib/ruby/gems/4.0.0/extensions/arm64-darwin-20/4.0.0-static/bootsnap-1.24.5
/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-1.6.0/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-1.7.15/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-0.6.13244/lib
/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/sorbet-0.6.13244/lib
/opt/homebrew/Library/Homebrew/vendor/bundle/ruby/4.0.0/gems/sorbet-static-0.6.13244-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-0.2.3-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-1.86.2/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-0.6.13244/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-0.3.12/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_1/lib/ruby/vendor_ruby/4.0.0
/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5_1/lib/ruby/vendor_ruby/4.0.0/arm64-darwin20
/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5_1/lib/ruby/vendor_ruby
/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5_1/lib/ruby/4.0.0
/opt/homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5_1/lib/ruby/4.0.0/arm64-darwin20
==> Homebrew Version
5.1.15-57-g7371776
==> macOS
26.5.1
==> SIP
Enabled
==> Homebrew Cask Staging Location
/opt/homebrew/Caskroom
==> Homebrew Cask Taps:
/opt/homebrew/Library/Taps/homebrew/homebrew-cask (7698 casks)
Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry or file an issue; just ignore this. Thanks!

Warning: Some installed formulae are deprecated or disabled.
You should find replacements for the following formulae:
  mdcat

tried also:

Code:

+  at 2026-06-06 06:13 [🔴 ERROR] brew tap
buo/cask-upgrade
homebrew/cask
homebrew/core

~
+  at 2026-06-06 06:19 [🟢 SUCCESS]brew untrust buo/cask-upgrade
Untrusted tap: buo/cask-upgrade

~
+  at 2026-06-06 06:19 [🟢 SUCCESS] brew update
==> Updating Homebrew...
Updated 1 tap (homebrew/cask).
==> Outdated Formulae
imagemagick                   mpv                           openjph                       sqlite

You have 4 outdated formulae installed.
You can upgrade them with brew upgrade
or list them with brew outdated.
Error: can't modify frozen Array: []

~ took 5s
+  at 2026-06-06 06:19 [🔴 ERROR] brew trust buo/cask-upgrade
Trusted tap: buo/cask-upgrade

Quotenfrau · Friday at 10:41 PM

Here the problem

Code:

brew tap buo/cask-upgrade
==> Tapping buo/cask-upgrade
Cloning into '/opt/homebrew/Library/Taps/buo/homebrew-cask-upgrade'...
remote: Enumerating objects: 1865, done.
remote: Counting objects: 100% (527/527), done.
remote: Compressing objects: 100% (184/184), done.
remote: Total 1865 (delta 395), reused 365 (delta 343), pack-reused 1338 (from 2)
Receiving objects: 100% (1865/1865), 269.54 KiB | 3.55 MiB/s, done.
Resolving deltas: 100% (945/945), done.
Error: can't modify frozen Array: ["buo/cask-upgrade"]

bogdanw · Friday at 11:06 PM

You could try
brew update-reset
https://docs.brew.sh/FAQ#:~:text=To%20undo%20all%20changes%20you,state%20on%20all%20Homebrew's%20repositories.

Lanik · Saturday at 8:00 PM

I've tried the brew update-reset as well

Bash:

→ brew update-reset
==> Fetching /opt/homebrew...
remote: Enumerating objects: 994, done.
remote: Counting objects: 100% (652/652), done.
remote: Compressing objects: 100% (110/110), done.
remote: Total 994 (delta 559), reused 542 (delta 542), pack-reused 342 (from 2)
Receiving objects: 100% (994/994), 3.27 MiB | 8.58 MiB/s, done.
Resolving deltas: 100% (630/630), completed with 395 local objects.
From https://github.com/Homebrew/brew
....

==> Resetting /opt/homebrew...
branch 'main' set up to track 'origin/main'.
Reset branch 'main'
Your branch is up to date with 'origin/main'.

==> Fetching /opt/homebrew/Library/Taps/beeftornado/homebrew-rmtree...

==> Resetting /opt/homebrew/Library/Taps/beeftornado/homebrew-rmtree...
branch 'master' set up to track 'origin/master'.
Reset branch 'master'
Your branch is up to date with 'origin/master'.

==> Fetching /opt/homebrew/Library/Taps/buo/homebrew-cask-upgrade...

==> Resetting /opt/homebrew/Library/Taps/buo/homebrew-cask-upgrade...
branch 'master' set up to track 'origin/master'.
Reset branch 'master'
Your branch is up to date with 'origin/master'.

==> Fetching /opt/homebrew/Library/Taps/homebrew/homebrew-cask...
From https://github.com/Homebrew/homebrew-cask
....

==> Resetting /opt/homebrew/Library/Taps/homebrew/homebrew-cask...
branch 'main' set up to track 'origin/main'.
Reset branch 'main'
Your branch is up to date with 'origin/main'.

==> Fetching /opt/homebrew/Library/Taps/homebrew/homebrew-core...
From https://github.com/Homebrew/homebrew-core
....
==> Resetting /opt/homebrew/Library/Taps/homebrew/homebrew-core...
branch 'main' set up to track 'origin/main'.
Reset branch 'main'
Your branch is up to date with 'origin/main'.

==> Fetching /opt/homebrew/Library/Taps/laniksj/homebrew-tap...

==> Resetting /opt/homebrew/Library/Taps/laniksj/homebrew-tap...
branch 'main' set up to track 'origin/main'.
Reset branch 'main'
Your branch is up to date with 'origin/main'.

I trimmed some stuff out with .... but otherwise you still get the "Error: can't modify frozen Array: []" error.

Quotenfrau · 2026-06-07T20:19:09-0700

I did also "brew update-reset"
Not a solution.
But thanks anyway.

bogdanw · 2026-06-07T23:44:01-0700

As I don't have Homebrew installed, but I'm curios 🙂, I’ve asked some “AI” agents.

ChatGPT insists it’s a Ruby exception..., not a problem with the Array itself, and says that brew update --debug should offer more information.

Claude says you can find the frozen array by running find $(brew --cache) -name "*.lock" and deleting what is locked should solve the problem find $(brew --cache) -name "*.lock" -print -delete

Copilot says that the most common cause is a broken tap such as buo/cask-upgrade and that untapping it fixes the issue immediately: brew untap buo/cask-upgrade

Gemini suggests, along the fixes already mentioned, manually clearing out Homebrew’s internal cache repository with
rm -rf $(brew --cache)/downloads/*

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06.2026: "brew update" gives error "Error: can't modify frozen Array: []"

Quotenfrau

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Bigwaff

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Quotenfrau

macrumors 6502a

Quotenfrau

macrumors 6502a

bogdanw

macrumors G3

Lanik

macrumors newbie

Quotenfrau

macrumors 6502a

bogdanw

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