[installer] 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.

[samuela]

Install failure:

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.

Can I just delete the nixbld group entirely and re-run the installer?

Platform

• Linux:
• macOS
• WSL

Additional information

I'm running macOS 15.0.1 (24A348) and have a pre-existing, broken nix install.

Output

Output

~~> Setting up the build group nixbld

---- oh no! --------------------------------------------------------------------
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.

We'd love to help if you need it.

You can open an issue at
https://github.com/NixOS/nix/issues/new?labels=installer&template=installer.md

Or get in touch with the community: https://nixos.org/community

Priorities

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[abathur]

What does "broken" mean here?

If you're running into errors that mention nixbld users when you run Nix commands, you may just need to run the migration procedure mentioned in the first post of the pinned issue:

• macOS 15 Sequoia clobbers _nixbld1-4 users #10892

[samuela]

What does "broken" mean here?

Broken in the sense that I expected the installer to automatically reuse or migrate existing nixbld users and the nixbld group.

If you're running into errors that mention nixbld users when you run Nix commands, you may just need to run the migration procedure mentioned in the first post of the pinned issue:

I'm seeing this error at nix installation time.

[abathur]

What does "broken" mean here?

Broken in the sense that I expected the installer to automatically reuse or migrate existing nixbld users and the nixbld group.

You said:

have a pre-existing, broken nix install.

In what way was that install broken?

[samuela]

In what way was that install broken?

Oh, apologies. I had a previous nix install that was broken after a macOS upgrade (I believe to 14?). I still had the /nix APFS volume but it wasn't being mounted for some mysterious reason. And I still had the nixbld group and its users. The exact state of the system may be hard to pin down but that's where I was at.

[abathur]

That sounds like the issue/fix in this thread/comment:

• Rebooting always unmount Nix volume in macOS Monterey 12.5 #6839 (comment)

I don't feel like I have a precise enough sense of where the system's at right now to feel comfortable recommending any specific minor surgery, so as long as wiping the store volume isn't a nonstarter I'd recommend:

1. Look into the recommendation linked above for the mount issue and follow its recommendations if you see those items toggled off. (I'm not myself certain whether this condition will persist through an uninstall, so this is to hedge against it doing so.)
2. Follow the uninstall instructions and then reinstall: https://nixos.org/manual/nix/stable/installation/uninstall.html#macos.

(If losing the Nix volume will be particularly painful, let's see how step 1 goes and re-evaluate.)

[samuela]

Thanks @abathur ! I ended up fixing by deleting the nixbld group and all its users and then re-installing nix with the official multi-user installation.