I have had to disable the network devices of my virtualbox too. VMWare and Hamachi could also be responsible to causing errors. You should also make sure your current internet connection is the one with highest priority (which should be default).
If you're using comodo internet security like me you need not to deinstall or disable it at all. Just make your sh5.exe an secure application within comodo security settings page AND tell your firewall the gameupdater (gu.exe) is an trusted application. If you want to play online sh5.exe must also be a trusted application within your firewall. Last tell comodo antivirus not to scan your sh5 directory (performance increase!). This should be the same for other firewalls/antivirus programs.
Unfortunately I've had crashes to my desktop as soon as the loading screen was about to change to my sub. I reinstalled windows
and now everything is working well.