superinterstellar, I don't think dropping the SQL tables is a good idea but disabling it in config worked for me, I then set the respective CardDav book as the primary and automatically added contacts got added there and there was no access to the SQL one, you could clear the table but removing it would probably cause issues.
Although the code that zhb exampled is wrong - it'd only stop the book from being added to the autocomplete ajax call,
you should do something like:

$config['address_book_type']         = '';
$config['default_addressbook']       = 'carddav_1';
$config['autocomplete_addressbooks'] = array('carddav_1');

first line disabling built in personal books,
second changing the default to YOUR configured CardDav book,
third allowing autocomplete from the CardDav book.
You'd need to replace carddav_1 with the full identifier of the Book that you create through the CardDav plugin in config.

To find the full identifier, you most likely will need to use Developer Tools in your browser to see what it has been named;
Go into Address Books in Roundcube
Open Developer Tools
Inspect one of the "Groups" buttons (the one you want to use as the default)
You'll see something like:

<a href="./?_task=addressbook&amp;_source=carddav_3" rel="carddav_3" onclick="return rcmail.command('list','carddav_3',this)">Contacts</a>

the rel= attribute will give you the name of it, and I've just noticed that for some reason mine is still default even though the id is different - weird xD

Default is just to tell roundcube which address book will be used by default. The plugin you are using must be configured to provide it, to roundcube the carddav book is no different than the regular one but managed by the plugin, by saying it's default, the add to contacts button will add to the carddav

i have the carddav plugin in my setting (with the same config settings that works on my phone)
its only on roundcube where the carddav data is not showing up in the addressbook.
guess i'll have to email the author. the link is below.

https://github.com/christian-putzke/Rou … ter/README

will contact him and ask him, might get a better understanding on why is this not working. it should work.

ah ok!
thanks
i picked it from the roundcube repository. someone needs to update the roundcube repository and remove outdated plugins and put up relevant ones.
thanks 7t3chguy.

i got rcmcarddav installed and it accepts my configuration. and i have it selected on activate
except when i go addressbook and try to make a search i get nothing.
any idea why?

need advise on how to troubleshoot.

i did. already spoke to the author.
suppose to have a log in roundcube/logs/carddav
i cant seem to have it? how do we turn on loggings?  any idea?
or will just look around.
thanks