I had VMware workstation 12.0 installed and running correctly under Windows 10 Pro RTM build. After upgrading to the latest Windows 10 Pro Insider Preview build 10565 VMware failed to start a VM with a vmci.sys error 'incorrect version' message.
The message is misleading, because the vmci.sys driver was no longer present under the \Windows\System32\drivers folder.
Rerunning the Install from the install.exe and choosing Repair restores the missing driver.
Chris.