MacBook Pro Screen turns black after Screen sharing with macOS 15.2

I have the same issue. I just bought a Mac mini and I am using it on my main display.

I have a MacBook Pro 14 that I am sharing on my Mac mini screen.

When I disconnect my Macbook pro and take it with me, the next time I open it, the MacBook's screen is dark and will not turn on.

I have been forced to hold the power button to shut it down, then restart the MacBoopk, and then the screen is back.

A work around for now I suppose is to shut down the MacBook so that when I turn it on, it starts up normally, but the screen should come back on after you stop sharing it. Am I doing something wrong or is this a bug?

<< I am connecting using the Screen Sharing App from my personal laptop to my corporate laptop. >>

I am quite certain of that.

But what I do not yet know is which Mac's virtual screen is appearing in a window on which Macs display?

<< using a USB-4 cable properly recognised as Thunderbolt bridge, but the problem is independent of using the TB/High Performance. >>

USB-C cables are suitable for LOCAL peripheral connections. They do NOT support computer-to computer connections. if that cable is seen as suitable for a computer-to computer connection via Thunderbolt Bridge it is indeed a Thunderbolt cable.

<< Every time I close the session either disconnecting from the Screen Sharing App from my personal MB or pressing the icon of Connection Sharing on the work laptop, the screen of the work laptop remains black. >>

<< My corporate laptop is usually in clamshell mode and it is the one sharing the screen to my personal one. >>

When you close the display, the computer SHOULD go to sleep. Apple carved out a tiny exception to normal operation to allow you to operate with the display closed in a very few situations with the display closed.

Apple clearly does not love supporting 'closed clamshell' feature, and have removed the support article that described how it was supposed to work. So there is no longer any step by step handbook of now it is supposed to work.

When the 'closed clamshell' article was in existence, they did spell out a few exception cases. almost all essentially said, "if it don't work, expect to open the display and start over."

I think THAT is the advice you should follow:

"if it don't work, expect to open the display and start over."

<< As soon as I open the Screen sharing session, the screens goes black. >>

That is NOT expected behavior.

It is possible that if the destination Window (on the remote computer) and the Source window (on the local computer) are different enough, they are both "adjusted" to a compromise resolution that both Appear to be able to attain. Sometimes those computed compromise resolutions are not quite right, and one of the displays goes dark.

So my recommendation would be to fiddle with the destination window resolution and see if you can get different results.

I use screen sharing to remotely control my Mac Pro, used as a server in the basement. There are some legitimate times when I see a blank screen-sharing Window.

But for me, I never use "full screen". That would be too confusing, and I sometimes want to drag and drop to my current computer. So I always maintain the screen sharing in a window. Also my local computer has a much larger display, so I can keep the shared window separate.

I think there is some possibility that your computers are working as designed, but screen sharing is still active. The correct screen sharing information if the remote computer's information is not available is a dark window. if you have also selected "full screen" it will be very difficult to understand what is happening.

if I connect to the remote Mac when its display is sleeping, the screen sharing window will be dark. If the remote Mac re-boots, I often get a dark window, and often a very large spinner. When it proceeds far enough to draw a login screen, I get the login screen in the sharing window instead.

I used full screen, but changed it to a window (ie. not Full screen). I opened the lid of my MacBook and the screen was dark as before, but since I was still sharing, I went to display preferences. I changed the color profile and the screen came back on. I changed it back and it stayed on. It's a hack, but at least it saves from having to restart the machine.

Apple should address this issue and detect when a screen is no longer being shared and turn the built in screen on when the computer is re-activated.

YOU know what you mean, but I can't quite tell from your description. Which screen are you sharing onto which other computer?