Failed to write session data (user) on localhost

Question

On win10 pro 64 I use WAMP Server 3.0.6 64bit for joomla localhosting So, there are two virtual hosts in server: interopt and gmdb The first works perfect but when trying to run the second it responses with

Warning: session_write_close(): Failed to write session data (user). Please verify that the current setting of session.save_path is correct (f:/wamp64/tmp) in F:\wamp64\www\gmdb\libraries\joomla\session\handler\native.php on line 194

Session_save_path looks correct while it's really placed on f:/wamp64/tmp (folder has read/write permissions

On 194 line of native.php is

session_write_close();

I use php version 7.0.10 (but the same problem appears when turnning on 5.6.25 too) virtual hosts seem work perfect and host file too

Any idea? Could you please help?

My virtual hosts

<VirtualHost *:80>
    ServerName localhost
    DocumentRoot f:/wamp64/www
    <Directory  "f:/wamp64/www">
        Options +Indexes +Includes +FollowSymLinks +MultiViews
        AllowOverride All
        Require all granted
    </Directory>
</VirtualHost>

<VirtualHost *:80>
    ServerName interopt
    DocumentRoot f:/wamp64/www/interopt
    <Directory  "f:/wamp64/www/interopt">
        Options +Indexes +Includes +FollowSymLinks +MultiViews
        AllowOverride All
        Require all granted
    </Directory>
</VirtualHost>

<VirtualHost *:80>
    ServerName gmdb
    DocumentRoot f:/wamp64/www/gmdb
    <Directory  "f:/wamp64/www/gmdb">
        Options +Indexes +Includes +FollowSymLinks +MultiViews
        AllowOverride All
        Require all granted
    </Directory>
</VirtualHost>