The Real Way:
It’s quite simple actually.
Open up messaging
swipe from the right for the charms bar (or hit control + c)
Toggle all messaging services Off
I think I found another way and it is a lot simpler than I thought. All you have to do is unpin the messaging app. Don’t uninstall it though because this will uninstall mail and calendar too. You might need to log on/off or reboot after you do this.
Basically you can’t in the Release Preview. It’s kind of annoying. Every time I log into my Windows 8 PC it also logs me in to Facebook and sets my status as available. There isn’t any way to log out of Windows 8 Messaging. The only control Microsoft gives you is over your visibility. It’s not that I want to ignore everyone; it’s that I don’t want to be logged into chat unless I choose to do so. It’s already annoying enough that I get logged into Facebook from Skype too. There was a time when I was getting bombarded with Facebook messages on my Windows Phone, Windows 8, Skype, and Facebook.com! One person sent one message and it was sent everywhere. That had to stop. So I found a pretty simple fix. Just create a firewall rule to block the communication. I know this is taking drastic measures but it is pretty easy to do and Microsoft hasn’t provided an alternative. I am sure they will fix this in the final release. Here’s how…
Hit the Windows Key then type CMD Right click Command Prompt and choose Run as administrator from the bottom.
Copy the following command: Windows 8 32-bit:
netsh advfirewall firewall add rule name=”MetroMessengerXMPP” action=”block” dir=”out” program=”c:\program files\windowsapps\microsoft.windowscommunicationsapps_16.2.3237.215_x86__8wekyb3d8bbwe\LiveComm.exe” remoteip=”22.214.171.124,126.96.36.199/24″
Windows 8 64-bit:
netsh advfirewall firewall add rule name=”MetroMessengerXMPP” action=”block” dir=”out” program=”c:\program files\windowsapps\microsoft.windowscommunicationsapps_16.2.3237.215_x64__8wekyb3d8bbwe\LiveComm.exe” remoteip=”188.8.131.52,184.108.40.206/24″
then right click the background of your command window then choose paste and hit enter.
There you go. You are blocking the messaging service. This should work as long as they do not change the IP. If you want to revert back, run the Advanced Firewall and delete the rule we just created. You can get to the Advanced Windows Firewall by running wf.msc from the start menu or command window.