Hotfix for User Profile Disk (UPD) Dismount Issues:
Glad to say that the October 2016 Monthly Rollup contains a hotfix for the present User Profile Disk dismount issues some of us have been experiencing (and complaining about). October 2016 Preview of Monthly Quality Rollup for Windows 8.1 and Windows Server 2012 R2 Addresses issue where the user profile disk (UPD) does not dismount when a user logs off. Therefore, users get temporary profiles and are not able to work with their own profiles during their next logon. The Event ID 20491 with a description of “Remote Desktop Services could not disconnect a user disk for the user account [...]