I concur with DrJagaloon, for me at least removing third party Bullguard AV software seems to have fixed issue - I was also getting occasional green screen after switching users, or reboot to a different account so will monitor that issue.
An addendum - what it may be worth checking is Windows Task Manager - in my case I have two users who regularly log on. What I noticed in the user's tab of task manager was that the second user was consuming resources even after a machine re-boot, when they hadn't even logged on. I right clicked the user and disconnected them - resources freed up and when I reboot, they no longer appear in the list.
My suspicion is that I ran the insider update when the other user was logged in and we had used the switch user capability, and it had somehow retained the settings so auto started the other user even after a reboot.
I also suspect that it was running AV, Search indexing and other processes that were very resource intensive so whilst removing Bullguard fixed the problem - it may simply have been masking the real issue, as neither problem has resurfaced since I disconnected the user.
This may help someone else so thought I would update just in case.
