The Joomla! Help page Users: New or Edit Group advises against editing User Groups:

"Joomla! is installed with set of User Groups suitable for management of standard sites. The default groups should not be edited! New groups can be created for special purposes."

expected behaviour

Please re-open. The help might say that but the documentation and the code doesnt. There is no mention of this restriction in Joomla 3 help pages.

If you cannot rename these groups "for some unknown reason" then they should not be editable and they should have a correct and meaningful error message. Not the current error message which is not helpful

In addition the information that "The default groups should not be edited" is totally wrong. There is no reason that any of them can not be edited. The only one with a problem is the root (public)

I just want to translate the group names to the language that is used in the backend, for our clients this is mostly dutch. So we want then to see dutch usergroup names. I see no reason why this should not be done? Maybe adding translation string to the usergroup could also help with this. But I am not sure that is technically possible.

We already changed the group names below the root public item. The root is the only one we could not change because of the error.

Hi,
I have exactly the same problem: After migrating a J3 site to J4, I noticed that the root group is named "Öffentlich". I now wanted to rename this to Public, simply to name the groups of clarity in all my Joomlas in the same way. That works good, except for the lowest level. Renaming from "Öffentlich" to "Public" is not possible. Presumably the parent level field is there and empty but hidden, hence the error message. The only way was to change the entry directly in the table via PhpMyAdmin.

If the name may not be change, the message is wrong. If the name can be changed then the parent name of "public" cannot be requested.

Technically the message is correct as it explains the technical reason why. However I would much prefer it if we could work out how to allow the group to be renamed instead of adjusting the message

Please update the label to j4 issue -

a valid reason for renaming all the groups is so that they can be presented in the users language and not in english.

Please test #38592

Closing as having a pull request. Please test #38592 . Thanks in advance.