Same issue in my laptop Lenovo G40-80 I think after some apt-get update/upgrade it has started. (Between 2 or 3 weeks ago)
I'm the only user of this computer. There is only my user and admin is disabled.
I use Virtual Box and it was upgraded recently to Version 5.1.34 r121010 (Qt5.5.1).
If I lock screen it don't happens immediately. It happens only after screen goes blank.
Then I have to click on "switch to greeter" in password field and wait some seconds to screen changes and I be able to insert password.
Same issue in my laptop Lenovo G40-80 I think after some apt-get update/upgrade it has started. (Between 2 or 3 weeks ago)
I'm the only user of this computer. There is only my user and admin is disabled.
I use Virtual Box and it was upgraded recently to Version 5.1.34 r121010 (Qt5.5.1).
If I lock screen it don't happens immediately. It happens only after screen goes blank.
Then I have to click on "switch to greeter" in password field and wait some seconds to screen changes and I be able to insert password.
# lsb_release -a 20160110ubuntu0 .2-amd64: core-9. 20160110ubuntu0 .2-noarch: printing- 9.20160110ubunt u0.2-amd64: printing- 9.20160110ubunt u0.2-noarch: security- 9.20160110ubunt u0.2-amd64: security- 9.20160110ubunt u0.2-noarch
LSB Version: core-9.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.4 LTS
Release: 16.04
Codename: xenial