There is a bug in ABI when using the MySQLi (with a trailing i) database driver. The escape doesn't work correctly and ends up assigning an empty password and email to that Super Administrator user. If you use the MySQL (without a trailing i) driver in the Restore DB page this won't happen. It's strange that this problem appeared only now. I traced it to a block of code written some 14 months ago. All this time this bug was there and nobody bumped into it until a week ago.
About the inability to edit the admin user, my guess is that Joomla! doesn't like not having a username and password. Using phpMyAdmin, edit the the jos_users table, find the "admin" account, then add an email address in the email field and a random string (e.g. "abcd") in the password field. This should allow you to edit the user.
I am fixing this issue right now and will publish a new release later today to address it.
Nicholas K. Dionysopoulos
Lead Developer and Director
π¬π·Greek: native π¬π§English: excellent π«π·French: basic β’ π My time zone is Europe / Athens
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