Mac desktop screen is black after sleep
Let us know the results, and have a good day. Then sign in to the new user account and see how it goes when you try changing your wallpaper. Check out this link for the exact steps to create a new account: Set up users, guests, and groups on Mac - Apple Support You can also test in a newly created administrator account, which will help work out if this issue is system-wide or user-account specific.
Once you start up in safe mode, see if you can set a wallpaper and then click Apple menu () > Restart. On either the first or second login window, you should see ”Safe Boot” in the upper-right corner of the window." The first basic solution to fix this problem is checking the screen brightness levels of your Mac.
Check Your Display/Monitor and Connections. Eventually, my web searches led me to believe this was caused by the xserver. If the black screen appears before you sign in to your computer, run through these fixes. Turning off screensavers and power saving did not have any effect. Note: I have no idea if its a permission issue, thats just my best guess. This will clean up any misplaced file permissions and now the VM will open correctly again. Obviously not desirable behaviour for an htpc. Here is the fix: If the VM opens with a black screen, close the window, log into your other Mac user, open the VM there and shut it down. While viewing videos on my htpc, the screen would blank after 10 minutes with no keyboard/mouse input.