Notice: Undefined index: name in wp-includes/class-wp-roles.php

That’s a PHP warning notice, and not an error or critical error. There are different levels of notices and errors: https://php.net/manual/en/function.error-reporting.php

You can really ignore it and turn off debugging to not fill the log. But if you want to fix it, you need to deductively find the theme or plugin that is causing it by deactivating all plugins and reactivating them one at a time; same with the theme.

Great, thanks Mark. I’ll give it a go before turning it off. Cheers, Karen

That should work for you.