Failed to create demo net driver

Development Platform & Builds
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1

When typing in console command : DemoRec demo1
console answers ‘Failed to create demo net driver!’

Its an FPS game and works with a dedicated server.
client builds connects on didicated server fine and game works as expected.

What’s catch?

2

Hi ,

I wasn’t able to reproduce this issue with 4.6.1. Which version of engine are you using? Can you reproduce this behavior in a new project, or only your existing project? Are you attempting this in editor, or in a packaged game? Any other details that might help us reproduce this internally?

3

Hello we are using 4.6.0. Our game was initially based on shooter game although it is heavily modified.
( https://www…com/watch?v=NnZAzvEd9wQ ).

We haven’t tried on an empty project, I think its not very useful unless you guys haven’t done it.

I do understand issue might be quite complicated to pin down, could you perhaps let me know what kind of information you need? I know you guys are hoping to have this feature work out of box and I think our project is a perfect test subject :slight_smile:

4

We ask if it happens in a new project because we need to see if it’s specific to a project or a bug that happens in all projects. If it doesn’t happen on our end, we need to see if it happens in all cases on your end. I couldn’t reproduce it, but you didn’t give many details for me to be sure that I’m following same steps you are:

  1. Are you attempting this in editor (with Dedicated Server enabled, in Selected Viewport or New Editor Window), or in a packaged game?
  2. Does this happen regardless of which client you use console command in, or does it only happen in some?
  3. If I were to attempt this with base ShooterGame project for 4.6, what exact steps would I need to take to reproduce it?

Thanks!

5

Hello ,

I tried it both in editor and in stand alone game on multiple computers. With standalone build I connect to a dedicated server, once spanwed I open console and type DemoRec test1, I then get error through console: Failed to create demo net driver!

In editor with dedicated server turned on I open a map, press play and run same console command. I get a console message saying how many actors are in level. If I try now DemoPlay test1 editor crash and I get following callstack:

6

MachineId:594389EC4A3802DBD53F658F34D9D806
EpicAccountId:0863b33f17c942ed9a2e5d37e40e6d9b

Access violation - code c0000005 (first/second chance not available)

UE4Editor_Engine + 9803865 bytes
UE4Editor_Engine + 9892999 bytes
UE4Editor_Engine + 9823051 bytes
UE4Editor_UnrealEd + 2614019 bytes
UE4Editor_UnrealEd + 6316416 bytes
UE4Editor_Engine + 3608163 bytes
UE4Editor_Engine + 5398506 bytes
UE4Editor_Engine + 6331109 bytes
UE4Editor_Engine + 14951895 bytes
UE4Editor_Engine + 15037392 bytes
UE4Editor_Engine + 15035151 bytes
UE4Editor_Engine + 3710415 bytes
UE4Editor_StormUnited!UShooterGameViewportClient::InputKey() + 132 bytes [d:\unreal\stu44\source\stormunited\private\shootergameviewportclient.cpp:13]
UE4Editor_Engine + 14630118 bytes
UE4Editor_Slate + 1552270 bytes
UE4Editor_Slate + 430514 bytes
UE4Editor_Slate + 155917 bytes
UE4Editor_Slate + 162282 bytes
UE4Editor_Slate + 828422 bytes
UE4Editor_Slate + 766664 bytes
UE4Editor_Core + 2484067 bytes
UE4Editor_Core + 2400747 bytes
UE4Editor_Core + 2489259 bytes
UE4Editor_Core + 2387170 bytes
user32 + 9268 bytes
user32 + 8855 bytes
UE4Editor_Core + 2490470 bytes
UE4Editor!FEngineLoop::Tick() + 3434 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.6\engine\source\runtime\launch\private\launchengineloop.cpp:2193]
UE4Editor!GuardedMain() + 479 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.6\engine\source\runtime\launch\private\launch.cpp:131]
UE4Editor!GuardedMainWrapper() + 26 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.6\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() + 249 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.6\engine\source\runtime\launch\private\windows\launchwindows.cpp:202]
UE4Editor!__tmainCRTStartup() + 329 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]
7

Hi ,

Sorry for long delay! This post got lost in shuffle somewhere, and I just found it again this afternoon. I tested this again, and I can confirm a crash when using DemoPlay in editor. This is actually already a known issue, reported in UE-6477.

I tested this in Standalone Game in 4.6, and it didn’t seem to be working properly either. In 4.7.1, however, DemoRec and DemoPlay appear to be working well in Standalone (and packaged) games. Have you attempted opening a copy of project in 4.7.1 to see if this works for you as well? If so, and issue is still occurring, please let me know here. Thanks!

8

Hello , no worries, thank you for following up.

I’ve just tested demorec in our latest standalone win 64 build using UE 4.7.2 and unfortunately we have same issue as in 4.6.1 : Failed to create demo net driver.

I have tried it in Editor and like before it appears to work by telling how many actors are int he scene but when I use demoplay it crashes editor instantly with following error callstack:

9

Hi ,

Playing in Editor and getting a crash on DemoPlay is a known issue, and probably won’t be addressed until 4.8.

Can you try in an unmodified ShooterGame project in 4.7.2? Here’s how I tested:

  1. Package ShooterGame for Win64
  2. Open ShooterGame.exe and host a game
  3. Open another instance of ShooterGame.exe and connect to host
  4. Open console and type “DemoRec test1”

Result:
Num Network Actors: 451

Are you setting this up differently?

10

Hey ,

I’m resolving this post for tracking purposes for now. When you get a chance to answer questions above, please comment here and we’ll keep investigating. Thanks!