Update: This issue has been fixed in the re-released KB3176938 update.
Today I ran into an error message on one of my systems. PowerShell was unable to import my remote session to Exchange Online.
Import-PSSession : Could not load type 'System.Management.Automation.SecuritySupport' from assembly 'System.Management.Automation, Version=220.127.116.11, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.
A quick Google search learned that this KB3176934 update was released a couple of days ago and is known to break DSC, remote PS and probably other stuff.
Microsoft scheduled an updated update to be released on the 30th of August 2016. If you can’t wait for some reason, for instance you planned to do some actual work today, uninstall the update and reboot your system.
wusa /uninstall /kb:3176934