Installer leaves behind a root-owned ~/Library/

[gurjeet]

• your problem was from running the official install or uninstall script?
• you carefully read the output and it was not a git fetch or other connection issue to GitHub (that Homebrew has no control over)?
• after installation: ran brew config and brew doctor and included their output with your issue? If you couldn't install: provided your OS version with the output of your issue?

What you were trying to do (and why)

On a macos guest/VM, I was trying to install a package that in turn depends on the ca-certificates package. I was trying to set up a reproducible development environment in a macos guest/VM.

What happened (include command output)

The brew install ca-certificates command exited with exit code 1. The root cause seems to be the fact that the Homebrew installer creates ~/Library/Cache/ directory with root as the owner, and then leaves it behind without fixing the permissions. So when the ca-certificates package's post-installation step tries to write to that directory, it fails to do so, since it's running as non-root user.

Command output

$ NONINTERACTIVE=1 /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
...
==> Installation successful!
...
$ ls -ld ~/Library/{,Caches/{,Homebrew}}
drwxr-xr-x   3 root     staff   96 Aug 30 02:48 /Users/vagrant/Library/
drwxr-xr-x   3 root     staff   96 Aug 30 02:48 /Users/vagrant/Library/Caches/
drwxrwxr-x  11 vagrant  staff  352 Aug 30 02:48 /Users/vagrant/Library/Caches/Homebrew
$ eval "$(/opt/homebrew/bin/brew shellenv)"

$ brew install ca-certificates

...

==> Pouring ca-certificates--2025-08-12.all.bottle.2.tar.gz

Warning: The post-install step did not complete successfully

You can try again using:

brew postinstall ca-certificates

...
$ brew config

HOMEBREW_VERSION: 4.6.7

ORIGIN: https://github.com/Homebrew/brew

HEAD: 02947ea4edbdef5fcce9ee57fa289547f4d096c9

Last commit: 5 days ago

Branch: stable

Core tap JSON: 30 Aug 02:48 UTC

Core cask tap JSON: 30 Aug 02:48 UTC

HOMEBREW_PREFIX: /opt/homebrew

HOMEBREW_CASK_OPTS: []

HOMEBREW_FORBID_PACKAGES_FROM_PATHS: set

HOMEBREW_MAKE_JOBS: 2

Homebrew Ruby: 3.4.5 => /opt/homebrew/Library/Homebrew/vendor/portable-ruby/3.4.5/bin/ruby

CPU: dual-core 64-bit dunno

Clang: 17.0.0 build 1700

Git: 2.39.5 => /Library/Developer/CommandLineTools/usr/bin/git

Curl: 8.7.1 => /usr/bin/curl

macOS: 15.6-arm64

CLT: 16.4.0.0.1.1747106510

Xcode: N/A

Rosetta 2: false
$ brew doctor

Your system is ready to brew.

What you expected to happen

I expcted brew install to finish successfully.

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

NONINTERACTIVE=1 /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
eval "$(/opt/homebrew/bin/brew shellenv)"
brew install ca-certificates

[gurjeet]

It seems to be a regression, since #279 looks exactly like the problem I describe here, except that that one's on Ubuntu and mine is on macos.

[ZhongRuoyu]

This should be fixed by #1025, but just to help us understand the cause of the issue: it seems that the directory ~/Library/Caches (or even ~/Library) does not exist before installing Homebrew. If that's the case, do you know why? This looks unusual because Apple's documentation ¹ suggests that this directory should be created by the system (well, it doesn't explicitly mention the Caches directory but I believe that this is the case).

Footnotes

1. https://developer.apple.com/library/archive/documentation/FileManagement/Conceptual/FileSystemProgrammingGuide/MacOSXDirectories/MacOSXDirectories.html ↩

[gurjeet]

@ZhongRuoyu The OS user in question (vagrant) was created using CLI, instead of using the GUI (System Settings.app). That may explain the missing ~/Library. Here's the complete script I used to create the OS user vagrant in a macos VM/guest managed by Tart.

# Create the vagrant user
dscl . -create /Users/vagrant
dscl . -create /Users/vagrant UserShell /bin/bash
dscl . -create /Users/vagrant RealName "Vagrant"
dscl . -create /Users/vagrant UniqueID 502
dscl . -create /Users/vagrant PrimaryGroupID 20
dscl . -create /Users/vagrant NFSHomeDirectory /Users/vagrant
dscl . -passwd /Users/vagrant vagrant
                                                                 
# Only the members of admin group are allowed remote/SSH login
dscl . append /Groups/admin GroupMembership vagrant
                                                                 
mkdir /Users/vagrant
# Copy the SSH configuration from the admin user
cp -r /Users/admin/.ssh /Users/vagrant/.ssh
chown -R vagrant:staff /Users/vagrant
                                                                 
# Enable password-less sudo access for vagrant user
echo 'vagrant ALL=(ALL) NOPASSWD: ALL' >> /etc/sudoers.d/vagrant

[ZhongRuoyu]

Thanks for the context, @gurjeet. The installer should be fixed now. You can manually fix the permissions of ~/Library{,/Caches} for your existing VMs.