multiple virtual machines causes freeze / hang / lockup

Hello,
I'm running the latest Parallels Desktop for Mac (build 5624), and I've noticed that when I attempt to run more than 1 virtual machine (2 linux, or 1 windows and 1 linux) that all the machines will effectively 'freeze' up when I launch more than 1. By stopping all machines except for 1, the machine will un-freeze. Has anyone else experienced this? I've tried changing settings to disable sound, virtualization, and other things I thought might conflict, with no luck.

-Jeremy

 

Check following:
Is there enough disk space on partition where VMs are located?