Recently, as another added security measure I decided to change the table prefix of my WordPress database in MySQL. Easy enough done, log in to phpMyAdmin and change all the wp_ to, well – whateveryoulike_
For example: wp_options becomes yournewprefix_options
The only catch here is WordPress actually saves some options using the wp_ prefix – within those aforementioned tables.
So, try logging in to wp-admin and you’ll get a ‘You do not have sufficient permissions to access this page’.
A little annoying, considering you can still use the front end of your site without issue.
The fix is to change the offending prefixes in _options, and _usermeta
What you’re looking for is _user_roles (in the _options).
_capabilities, _user_level and possibly _autosave_draft_ids (in the _usermeta).
Once you have updated your prefixes here, you’ll be able to log back in without a problem.