Auto logout results in severe login screen bug With auto logout enabled, I experience severe display errors at the login screen. These errors do not occur at the login screen right after boot. They appear only when the auto logout is triggered.
I wonder if it's a hardware bug. A major flaw has been discussed at discussions.apple.com (166 pages!!). However, that bug is different and happened with Nvidia GPUs. I have a AMD Radeon HD 6490M (early 2011).
Question

What causes this bug? (hardware? software?)
What measures should I take?
Problem solved
In System Preferences &gt; Energy Saver the timers for display sleep and computer sleep must be greater than the time of auto logout after inactivity in System Preferences &gt; Security &amp; Privacy.