Hi Laura

I see potentially a few areas where something may be going wrong.

1) pre_get_posts is an action, however our sf_edit_query_args is a filter, and you are trying to combine the two

2) Our docs mention you should not use pre_get_posts and use our own filter instead.. Therefor, you must use our filter as per the docs:
add_filter( 'sf_edit_query_args', 'filter_hide', 20, 2 );

3) Your second code snippet should be close to working once you get it setup with our filter rather than pre_get_posts, however, I see another line where I’m not sure the logic is correct, I see you are trying to set author__not_in.. I’ve not used this before but assume it for excluding authors? If its like post__not_in then it will take an array of IDs..

I see you are using $meta = get_user_meta(get_current_user_id(), 'hide', true); to get teh values for this field – what does this get? It doesn’t look like it gets the Author IDs that you want to exclude from your search? Why not try as a test excluding some author IDs that are known to you, so this should really be:
$meta = array(1, 22);
If the authors you wanted to exclude had the IDs of 1 and 22

4) Then finally, you are setting your exclude authors into the variable $args but then you return a different variable, $query_args, so your changes are not being used at all or passed back to S&F…

I’ve rewritten your code (untested) in to how it should look:

function filter_hide( $query_args, $sfid ) {

	//$meta = get_user_meta(get_current_user_id(), 'hide', true);
	
	//if search form ID = 2259, then hide authors' posts
	
	if($sfid==2259)
	{
		//these are the Author IDs you want to exclude
		$query_args['author__not_in'] = array(1, 10); 
	}
	
	return $query_args;

}
add_filter( 'sf_edit_query_args', 'filter_hide', 50, 2 );

If you wanted to hide only the current users posts you would change 1 line above to something like:

$query_args['author__not_in'] = array(get_current_user_id());

Hope that helps