I have run into this on a couple versions of Parallels desktop business edition. 10 something up to the latest 12.1.3 (41532). Including un-installing and re-installing completely. Both the windows system and mac system lock after the set time. If the mac system is not used for 30 minutes to an hour after it locks. We see the mac lock screen when trying to get back into it. After logging into there. Nothing seems to change. The mac login screen doesn't clear to show the mac desktop, windows vm lock screen, etc. We can swipe to the right and see the mac desktop. If we click on the vm or parallels. It switches us back to that side. But shows the mac login screen still. Which is unresponsive. After many of these occurrences on a couple different macs. We discovered that if you do the ctrl-alt-del after logging into the mac side. The windows vm lock screen will sometimes show up. At that point you can log in normally. If it doesn't. We can't get the vm or parallels to close without rebooting the mac. We are running on OS 10.11 and 10.12. It does the same on both OS versions.
