I need to change the admin user name but it won’t let me change it even though it’s the same password as the login

You can't change the name while logged into that user.

You'd be better off creating a new user account with the name you want and set it to administer the computer.

Transfer data from old Admin to new admin, then delete the old admin account.

You'll need another admin account, anyway as changing the account name often causes it to lose admin privileges, among other problems.

Thank you Barney-15E

You approach seems straight forward. Copying all data from the previous admin account should include programs and several virtual machines. Should I expect them to function as they previously had? The OS will now be Mojove though so the OS files should not be copied over - as long as I can identify them. This is be beyond my experience.

Using the same user name under the renamed admin account, should also permit time machine backups to be available I would hope.

Art

You will need to create you new user and log into it.

Get Info on the old user's home folder and add the new user to the list in the Sharing and Permissions. Set it to read/write.

Copy the data you need from the old folder into your new home folder.

Applications are not normally stored in the user's folder, so that shouldn't be an issue. Support data is stored in the user folder, usually in the ~/Library/Application Support/ folder. Sometimes apps will just create a folder in ~/Library.

The VMs are just files, so they should have no problem when you open them in the new user folder.

Using the same user name under the renamed admin account, should also permit time machine backups to be available I would hope.

I don't understand this. The point was to change the user name on the account. However, you won't be able to access the backups stored in the old user folder. You can get to them, but not in the normal manner.

..but since I can't open my locker I can't create or ad a new user account...and as the name I set to admin is now set to standard where can I see what the admin I can use to ad accounts for new users, groups etc is set to be?

where can I see what the admin I can use to ad accounts for new users, groups etc

You have to create one following these instructions: http://www.theinstructional.com/guides/how-to-re-run-the-os-x-setup-assistant