[Samba] Win 8 explorer.exe hangs randomly

[Eros Comin]

Hello to everyone!
I set up a Samba AD/DC server from git.
Samba version is 4.1.4 stable on Debian Wheezy.
Everything seemed to work fine, even password management, ACLs, windows admin tools, GPOs and folder redirection.
My network is very very small: only 3 clients: 2 Windows 8.1 Pro and 1 test VM Win 7 Pro.

When I raise the workload about file transfer and share access, I even start to face a very boring issue.
I mean that if I start to go in and go out to network share or start to make a file transfer like syncing Offline files, Explorer.exe hangs.
That behaviour happens only with Win 8.1, meanwhile trying to access to the same SMB server using Win7 Pro every works fine.
At that moment all I can do is to restart samba server or restart my PC.
This issue happens often.
Debian machine is a Citrix XenServer 6.2 VM.

This is my smb.conf:

#####################################################################
# Global parameters
[global]
        workgroup = DOMAIN
        realm = DOMAIN.LOCAL
        netbios name = SERVER
        server string = %h Server
        server role = active directory domain controller
        dns forwarder = 8.8.8.8
        case sensitive = no

## Opzioni di connessione e sicurezza. Configurazione WINS.

        guest ok = no
        name resolve order = wins lmhosts host bcast
        time server = yes
        panic action = "/usr/sbin/service samba restart"

## Configurazione dei log ###
       log file = /var/log/samba/log.smbd
       log level = 2
       max log size = 50


### Impostazione charset corretto ###
       hide unreadable = yes
       hide dot files = yes
       unix charset = ISO8859-1
       dos charset = CP850

## Sistema di stampa
       load printers = no
       disable spoolss = yes

[netlogon]
        path = /home/samba/sysvol/domain.local/scripts
        read only = No

[sysvol]
        path = /home/samba/sysvol
        read only = No


[homedirs]
        path = /home/samba/homedirs/
        read only = no

[profiles]
        path = /home/samba/profiles/
        read only = no


#####################################################################


Thank you.

--
Vash83