Will not wake screen from sleep, BLACK SCREEN. OS Catalina

This same exact thing is happening to me as well. I updated to Catalina and ever since, on wake it just displays a "black" screen. But, the computer isn't sleeping as my Apple Watch makes the "unlock" sound and vibration telling me it unlocked my iMac and my keyboard lights come on.

I have an iMac (Retina 5K, 27-inch, 2017).

I tried to reset the PRAM but couldn't seem to be able to do that. I did reset the Mac's SMC, but that didn't work.

Did not work for me either. If I close the screen right away, it will come back. However, normal use has my screen lock and close lid. I tried everything I've seen suggested, including the safe mode, but the issue still remains. My watch unlocks the screen - I can hear sounds - just no display. There is enough out there (through the betas and now gold release) that this is a major issue that needs to be addressed.

Noteworthy: multiple reports of this problem, but no fix or response from Apple. Same with Catalina breaking Time Capsule. This release has definitely been rushed to market and isn't much more than another beta-build. If the bugs being reported so quickly are this numerous who can tell how much is really broken "under the hood."

I have a definite fix that I'm implementing as soon as I post this.

Recover from backup and wait for Apple to get their OS together.

Good idea to remove the start-up items. Tried it, but didn't work. But that did get me thinking so thanks for that.

Here's what did work for me ... so far,

Enable the energy saver setting "Prevent computer from sleeping automatically when the display is off."

The overpaid developers in Cupertino should have caught this before they released this mess. Mine has a 1Tb hybrid drive, a known product that code-jockey's have been trying to back away from understanding since Apple release this iMac build.

End result is I'll probably roll-back to Mojave again and wait to see if a patch ever gets released. Catalina means I either keep the computer running all the time or shut down after each use - which would be okay if it was Redmond explaining why Windows Vista was such a really cool OS. So there you go. So far, Catalina impresses me almost as favorably as Windows Vista.

Thanks, the upgrade solved the problem for me as well. However, in trying to diagnose the problem knowing that it worked in safe mode. I noticed that I was loading a displaylink kernal extention for support of external usb video adapter. It was not being loaded in safe mode. The upgrade to the latest version of Catelina removed this kext from loading. I can't prove that this was the issue. If I was still having the issue I would explore this further as a potential solution.

The same here with a 2018 iMac. power is on (screen is dark grey) but n response. have to do a hard reset

I'm having the exact same problem on the same speed computer. Reset SMC and tried to reset PRAM but no love. Is there a way to roll back to 10.14?

My mom updated today, computer doesn't even look like it's booting.

Unfortunately this didn't work for me. After returning to normal (non-safe mode) the same black screen returns after going to sleep.

Did not work for me either.

Still having the issue....

Upgrade to 10.15.1 as it remedied the issue on my MacBook Pro, 13", 2018, Four Thunderbolt