Separate names with a comma.
Update: it seems like this can also happen after I try to close the Parallels app. So, the VM will close and quit, then the 'Parallels Desktop'...
I've read the http://kb.parallels.com/en/122767 (but, I'm not using an iMac) and http://kb.parallels.com/116263 (which I have done - it did stop...