KB2619234 update not installed [Win7RpcHttpAssocCookieGuidUpdateNotInstalled]
Exchange Server 2016 Setup can't continue because the local computer requires a software update. You'll need to install this update before Exchange 2016 Setup can continue.
Exchange 2016 Setup requires a Windows Server update that allows Outlook Anywhere (RPC over HTTP) to work correctly.
Download and install the 64-bit update from KB2619234, and then click retry on the Readiness Checks page.
Note
If this update requires a reboot to complete installation, you'll need to exit Exchange 2016 Setup, reboot, and then start Setup again.
Having problems? Ask for help in the Exchange forums. Visit the forums at: Exchange Server.