After first attempt to install on WordPress localhost plugin I got this error:

Connection Information
To perform the requested action, WordPress needs to access your web server. Please enter your FTP credentials to proceed. If you do not remember your credentials, you should contact your web host.

Solution:

Step 1.

Put into config.php define(‘FS_METHOD’, ‘direct’);  Parameter “direct” forces use of Direct File I/O requests from within PHP. Delete this line if you copy your whole WordPress installation on life host (security treat).

Step 2.

Unfortunately this is not all. When you download the theme or plugin it will not create the directory inside your folder.

It is necessary to change permission on main folder of WordPress installation.

In order to change the folder permission you need to right click on the root folder directory of your site. Click “Get Info”  and unlock (bottom right) access. by giving your admin password. Change permission settings for your folder according picture below and click on the gear icon “apply to enclosed items”.

Error looked like this:

Warning: simplePie/cache is not writeable. Make sure you’ve set the correct relative or absolute path, and that the location is server-writable. in /Applications/XAMPP/xamppfiles/htdocs/xxxxxxxxx/simplePie/library/SimplePie.php on line 1369

I browsed internet and first counter measure is to define absolute path to SimplePie cache folder from this:

$feed->set_cache_location('simplePie/cache');

to this:

$feed->set_cache_location($_SERVER['DOCUMENT_ROOT'] . '/xxxxxxxxx/simplePie/cache/');

or any other possible way to define absolute path in file.

Second counter measure is to set proper permission on folder where cache is made. I used Double Commander in OSX.