BSOC (Black Screen of Comatose) UE 4.5

This isn’t a show-stopper but I can reproduce it (and avoid it).

Basically, I can cause a temporary ‘black screen’ with my system being completely unresponsive for 90 seconds
until (I think) the NVidia driver ‘times out’.

My NVidia drivers are fairly recent, about 3 months out of date (see dxdiag attachment) so I don’t think that is
the issue but will update if no one else has this problem.
Other than this specific procedure — UE4.5 renders perfectly fine:

Create First Person Blueprint project

Save all, and package the project as a Windows 64bit exe

Run the exe

Click the Maximize-window button for the launched exe window.
(Press your Windows->Start button and then click the exe window caption bar if the mouse won’t go there)

Press ALT+ENTER to make the viewport full screen.
(Question: Does ALT+ENTER create a maximized window without a caption bar/frame or is it a kind of
‘DirectX Exclusive Fullscreen’ mode?)

-Black Screen Of Comatose-
On my system the screen goes black and system/keyboard is unresponsive.
(I cannot task switch or use CTRL+ALT+DELETE to display task manager).

After 90 seconds the Windows [Close program] dialog appears and allows me to kill
the exe window.

My DxDiag.txt specs

Hey ash22,

Whenever I follow your repro steps in the binary build of 4.5.1, I don’t end up with the black screen/freeze you describe. It does take a few seconds for the window to maximize, but nothing near 90 seconds. I would recommend upgrading your driver first.

Are you seeing the same issue if you alt+enter maximize without maximizing the window via the ‘Maximize Window’ button first?

Hi Jonathan,
ALT+ENTER is fine on its own (without maximizing).
It is only an issue with the ALT+ENTER with maximized window.
I also had the issue in 4.4 but not in 4.3 or 4.2.
I will update my drivers nonetheless.


I did notice that whenever my BSOC occured previously it seemed to coincide with the UE Launcher hanging or crashing out earlier (it does so from time to time for some unknown reason). I’m not aware of any depencency between the Launcher and the Engine so assumed it was just coincidence.

However, today I ran the launcher and it upgraded itself.

Out of curiosity I went through the same BSOC procedure as above - but this time it works with no black screen.
The only difference is now an exe will start in ‘full screen mode’ and only go to windowed mode after I press ALT+ENTER (instead of the other way around). I did not update my drivers so assume it is just some wierd quirk.

Pending question:
Does ALT+ENTER create a maximized window without a caption bar/frame or is it a kind of ‘DirectX Exclusive Fullscreen’ mode?

I’m not seeing the issue in 4.4.3 either. Your graphics card is well above our recommended card, so that shouldn’t be a problem. That’s why I’m thinking the drivers may be a factor.

I’m glad to hear the BSOC problem isn’t happening anymore - it’s possible that the issue was somehow related to the launcher. I’ll investigate this more if any other user has a similar issue in the future.

As for your pending question, I believe that alt+enter is just the standard windows ‘Full Screen’ mode, like many video games use (it shouldn’t be a DirectX exclusive, to my knowledge). It isn’t just a maximized window with no border (usually called ‘Borderless Windowed’ mode), which is clear from the time it takes to alt+tab out of that window. Alt+tabbing from a maximized window is fairly swift, but alt+tabbing from a ‘Full Screen’ window takes much longer.

Understood, thanks Jonathan.

The reason I ask this particular question is because I noticed in windowed mode my DrawText fonts (pt size=16) look fine as sharp as expected) but when I ALT-TAB into the fullscreen mode the same DrawText is blurred.

If I import the same font at (pt size=72)and scale it down it is not blurred but is distorted so that doesn’t work either.

Do you know why that is or how to preserve the font/text clarity?
This question is rather off-topic, so feel free to repond here if you have any ideas.

I’ll look into that issue for you, sure.

Fyi, the screenshot shows the Arial in various sizes in Windowed mode.
It is crisp and as expected.
(It is sharper if you download the image).

However, If I ALT+ENTER all the text is noticably blurred.
Unfortunately I can’t show a fullscreen screenshot because I can’t get one. The Console:HighResScreenShot command doesn’t output a 000.bmp in full screen mode (Fraps and the PrintScreenKey don’t work either).

Try cooking a Windows 7 64bit exe with [this project][2]
and let me know if the font loses its sharpness when you ALT+ENTER to fullscreen.