Mac OS 26 Error [Solved]

[yuazi]

Output of brew config

brew config                                                        
/opt/homebrew/Library/Homebrew/os/mac/version.rb:41:in `initialize': unknown or unsupported macOS version: "26.0" (MacOSVersionError)
	from /opt/homebrew/Library/Homebrew/os/mac.rb:37:in `new'
	from /opt/homebrew/Library/Homebrew/os/mac.rb:37:in `full_version'
	from /opt/homebrew/Library/Homebrew/os/mac.rb:27:in `version'
	from /opt/homebrew/Library/Homebrew/os.rb:59:in `<module:OS>'
	from /opt/homebrew/Library/Homebrew/os.rb:7:in `<top (required)>'
	from /opt/homebrew/Library/Homebrew/global.rb:77:in `require'
	from /opt/homebrew/Library/Homebrew/global.rb:77:in `<top (required)>'
	from /opt/homebrew/Library/Homebrew/brew.rb:22:in `require_relative'
	from /opt/homebrew/Library/Homebrew/brew.rb:22:in `<main>'

Output of brew doctor

opt/homebrew/Library/Homebrew/os/mac/version.rb:41:in `initialize': unknown or unsupported macOS version: "26.0" (MacOSVersionError)
	from /opt/homebrew/Library/Homebrew/os/mac.rb:37:in `new'
	from /opt/homebrew/Library/Homebrew/os/mac.rb:37:in `full_version'
	from /opt/homebrew/Library/Homebrew/os/mac.rb:27:in `version'
	from /opt/homebrew/Library/Homebrew/os.rb:59:in `<module:OS>'
	from /opt/homebrew/Library/Homebrew/os.rb:7:in `<top (required)>'
	from /opt/homebrew/Library/Homebrew/global.rb:77:in `require'
	from /opt/homebrew/Library/Homebrew/global.rb:77:in `<top (required)>'
	from /opt/homebrew/Library/Homebrew/brew.rb:22:in `require_relative'
	from /opt/homebrew/Library/Homebrew/brew.rb:22:in `<main>'

Description of issue

can't run brew update too.

Any ideas?
try

[gromgit]

Try brew update-reset, then brew config and brew doctor.

[AAAimer]

omg!! thanks!!

[ruialves92]

Thanks. Does not work on 26.3 yet

[SMillerDev]

26.3 is definitely supported. If this is not working for you there must be another reason

[KeepHot]

26.3 is definitely supported. If this is not working for you there must be another reason

same question

[SMillerDev]

What does your brew config say?

[yuazi]

It worked thanks a lot!!

[MasaruKitajima]

Thank you!
It solved.

[huashuiwujiale]

Thank you!

[karenlo-tt]

I am having the same issue but for MacOS 26.0.1.

Error: Fetching /opt/homebrew failed!
/opt/homebrew/Library/Homebrew/macos_version.rb:53:in 'MacOSVersion#initialize': unknown or unsupported macOS version: "26.0.1" (MacOSVersion::Error)
	from /opt/homebrew/Library/Homebrew/os/mac.rb:44:in 'Class#new'
	from /opt/homebrew/Library/Homebrew/os/mac.rb:44:in 'OS::Mac.full_version'
	from /opt/homebrew/Library/Homebrew/os/mac.rb:32:in 'OS::Mac.version'
	from /opt/homebrew/Library/Homebrew/os.rb:60:in '<module:OS>'
	from /opt/homebrew/Library/Homebrew/os.rb:7:in '<main>'
	from <internal:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/3.4.3/lib/ruby/3.4.0/rubygems/core_ext/kernel_require.rb>:37:in 'Kernel#require'
	from <internal:/opt/homebrew/Library/Homebrew/vendor/portable-ruby/3.4.3/lib/ruby/3.4.0/rubygems/core_ext/kernel_require.rb>:37:in 'Kernel#require'
	from /opt/homebrew/Library/Homebrew/vendor/portable-ruby/3.4.3/lib/ruby/gems/3.4.0/gems/bootsnap-1.18.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in 'Kernel#require'
	from /opt/homebrew/Library/Homebrew/global.rb:138:in '<top (required)>'
	from /opt/homebrew/Library/Homebrew/brew.rb:18:in 'Kernel#require_relative'
	from /opt/homebrew/Library/Homebrew/brew.rb:18:in '<main>'

I've tried brew update and brew update-reset but am still getting this error.

[karenlo-tt]

It turns out my ssh configs were outdated and interfering with brew update-reset. Once I opened a new terminal, it worked. Apologies for confusion and thanks for the help.

[julienbourdeau]

Im in the exact same situation but nothing wrong (as far as I know) with my ssh config.
brew update-reset didn't fix it and didn't print anything.
I also reinstalled homebrew with /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)" but nothing changed.

Any idea what when wrong?

---

❯ brew update
Initialized empty Git repository in /usr/local/Homebrew/.git/
fatal: not in a git directory

❯ git -C /opt/homebrew remote -v
origin	git@github.com:Homebrew/brew (fetch)
origin	git@github.com:Homebrew/brew (push)

❯ brew doctor
/usr/local/Homebrew/Library/Homebrew/macos_version.rb:42:in `initialize': unknown or unsupported macOS version: "26.0.1" (MacOSVersion::Error)
	from /usr/local/Homebrew/Library/Homebrew/os/mac.rb:42:in `new'
	from /usr/local/Homebrew/Library/Homebrew/os/mac.rb:42:in `full_version'
	from /usr/local/Homebrew/Library/Homebrew/os/mac.rb:29:in `version'
	from /usr/local/Homebrew/Library/Homebrew/os.rb:60:in `<module:OS>'
	from /usr/local/Homebrew/Library/Homebrew/os.rb:7:in `<top (required)>'
	from <internal:/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/3.3.4_1/lib/ruby/3.3.0/rubygems/core_ext/kernel_require.rb>:37:in `require'
	from <internal:/usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/3.3.4_1/lib/ruby/3.3.0/rubygems/core_ext/kernel_require.rb>:37:in `require'
	from /usr/local/Homebrew/Library/Homebrew/global.rb:136:in `<top (required)>'
	from /usr/local/Homebrew/Library/Homebrew/brew.rb:18:in `require_relative'
	from /usr/local/Homebrew/Library/Homebrew/brew.rb:18:in `<main>'

[SMillerDev]

It seems you're running brew with Rosetta, because the first command thinks it's on Intel when your install is located like it is on Apple Silicon.

[julienbourdeau]

Thanks @SMillerDev
I had to uninstall everything, reinstalled and I had the issue again. So I rm -rf /usr/local/Homebrew/, then reinstall again and it seems fixed 🙏

[julienbourdeau]

It seems that the important piece missing was eval "$(/opt/homebrew/bin/brew shellenv)" in my config.fish. It case that helps anyone else.

[TEBOUDA]

This worked for me:
Since brew update fails, force a manual update:

cd /opt/homebrew
git fetch origin
git reset --hard origin/master

Then for the core tap:

cd /opt/homebrew/Library/Taps/homebrew/homebrew-core
git fetch origin
git reset --hard origin/master

Same for cask:

cd /opt/homebrew/Library/Taps/homebrew/homebrew-cask
git fetch origin
git reset --hard origin/master

Then try again:

brew update --verbose

[SMillerDev]

That's exactly what this answer does: #6249 (comment)

[TEBOUDA]

That's exactly what this answer does: #6249 (comment)

Yet it only worked for me the way I mentioned it in my answer.

[QinghangPeng]

manual update is worked for me, the "brew update-reset" command failed to update my homebrew and instead caused the "brew" command to become unrecognizable