Thanks for the link to BugReport! I did not know about that before since I am still new to Apple after developing on Windows for the past 17 years. I just submitted this there with issue #15550585 and linked it back to this thread. Here is the text of my report:
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15550585 - Black screen if attempting to prevent sleep
Summary:
On any mid-2013 MBA (11" or 13"), when system is idle long enough to dim the display/go to sleep, the screen fades to black. If the user tries to prevent sleep by tapping a key or trackpad, the system hangs with a black screen. The CAPS LOCK key toggles on/off when pressed, but no other user input seems to do anything. Closing the screen and reopening has no effect. Only a hard boot will bring system back. The happens whether on battery or plugged in. Any unsaved documents/code files are lost.
Steps to Reproduce:
1. Let system idle and wait for display to dim (based on power settings).
2. Wait a couple more seconds for screen to go black.
3. Wait a split second more for keyboard backlight to begin to fade.
4. Before keyboard backlight is completely off, press a key or swipe the trackpad (as if trying to prevent the system from sleeping, thus requiring re-entry of password)
Expected Results:
I would expect the system to wake up and let me continue with what I was doing.
Actual Results:
When touching the input as the keyboard backlight is fading, the backlight illuminates brightly, but the screen stays black. The CAPS LOCK key will toggles its light on/off. No other action will wake up the system. Only a hard boot will bring system back on.
Version:
My personal machine is a mid-2013 MBA, 11", 256GB SSD, 8GB RAM, i7 chip, currently running Mavericks, but issue first noticed out-of-box running Mountain Lion.
Notes:
I brought my MBA to an Apple Store on 11/2/2013 and demonstrated the behavior to a "genius" with my configuration running Mavericks and when booting to Apple's "known good" environment running Mountain Lion. My case number is 524999600. I first announced my findings on the following discussion thread with the username "Yoganinja": https://discussions.apple.com/thread/5475679. Many others have been able to reproduce.
Configuration:
Any mid-2013 MacBook Air. Off-the-shelf models, brand new or refurbished. Custom models, brand new or refurbished. 11" or 13". Mountain Lion or Mavericks. Out of the box, or with additional software installed.