My desktop at home is running Windows 8.1 x64 with 16gb and VMware workstation 10.0.3.
I've been having issues with running guests where VMware will suddenly halt the guests and a dialog box appears saying it couldn't allocate memory for the guest. The guests have been up for a few days and (until now) was working fine.
A link on the dialog box points to a kb article addressing that error stating either more physical memory has to be added (the system supports no more than 16gb) or reduce the number of running applications to free memory.
The amount of memory used is only hitting about 50% as task manager is showing 7.9gb free and the 2 guests that were running are only configured for 1gb or 2gb. One guest is Windows 2012 and the other CentOS. Last time this happened (a week or two ago) there was an XP guest running. I was able to reboot the host last time to resolve it since shutting all other applications down and getting to about 14gb of free ram still wouldn't allow a 1gb guest to start. I've looked around a bit and found articles related to not being able to start a guest; for me it happens while running.
After upgrading to 8.1 I did completely remove VMware workstation and reinstalled it and has been working fine except for these memory messages. Not sure if it's a VMware or Windows issue, though leaning more towards Windows - perhaps memory management?.