Black screen with white apple and 20 white vertical bars on wake-up
Hi ~ After my mid-2012 MacBook Pro is woke up after being unused for about a half a day or so, it shows a black screen with the regular white apple, plus a row of about 20 rounded white bars below. This stays on for about 20 seconds, then all works fine after that.
What does this indicate, please?
Thanks much in advance!
Sure, Dan. Thank you