One of this month's updates, KB2995388, is reportedly causing issues with VMware Workstation 10 running on a Windows 8.1 host.
When the virtual machine is powered on, users are finding an error message stating that there is "not enough physical memory."
VMware is aware of the issue. The company is suggesting that you hold off installing the update until they can work up a patch, but if you have already installed it the workaround is to simply uninstall it.
One other workaround is start VMware Workstation using administrator rights.
VMware's statements on the issue are here: Workstation 10 issue with recent Microsoft Windows 8.1 Update