Friend's game is crashing whenever he attempts to connect to my server (no mods)

[OleHooklip]

Hosting a multiplayer game, no mods. Friend's game crashes as soon as he loads into the server. He's playing on a fresh install of the game. We're kind of at a loss on what to do next to try to fix this issue. Any assistance would be very much appreciated.

His crash log reads:

Game Version: v1.21.4 (Stable)
10/12/2025 8:20:35 AM: Critical error occurred
Loaded Mods: game@1.21.4, creative@1.21.4, survival@1.21.4
System.NullReferenceException: Object reference not set to an instance of an object.
   at Vintagestory.Client.NoObf.ClientSystemStartup.HandleServerIdent(Packet_Server packet) in VintagestoryLib\Client\Systems\Startup.cs:line 191
   at Vintagestory.Client.NoObf.ClientMain.ExecuteMainThreadTasks(Single deltaTime) in VintagestoryLib\Client\ClientMain.cs:line 786
   at Vintagestory.Client.GuiScreenRunningGame.RenderToPrimary(Single dt) in VintagestoryLib\Client\MainMenu\Screens\GuiScreenRunningGame.cs:line 172
   at Vintagestory.Client.ScreenManager.Render(Single dt) in VintagestoryLib\Client\ScreenManager.cs:line 719
   at Vintagestory.Client.ScreenManager.OnNewFrame(Single dt) in VintagestoryLib\Client\ScreenManager.cs:line 663
   at Vintagestory.Client.NoObf.ClientPlatformWindows.window_RenderFrame(FrameEventArgs e) in VintagestoryLib\Client\ClientPlatform\GameWindow.cs:line 112
   at OpenTK.Windowing.Desktop.GameWindow.Run()
   at Vintagestory.Client.ClientProgram.Start(ClientProgramArgs args, String[] rawArgs) in VintagestoryLib\Client\ClientProgram.cs:line 338
   at Vintagestory.Client.ClientProgram.<>c__DisplayClass10_0.<.ctor>b__1() in VintagestoryLib\Client\ClientProgram.cs:line 133
   at Vintagestory.ClientNative.CrashReporter.Start(ThreadStart start) in VintagestoryLib\Client\ClientPlatform\ClientNative\CrashReporter.cs:line 95
Game Version: v1.21.4 (Stable)
10/12/2025 8:28:54 AM: Critical error occurred
Loaded Mods: game@1.21.4, creative@1.21.4, survival@1.21.4
System.NullReferenceException: Object reference not set to an instance of an object.
   at Vintagestory.Client.NoObf.ClientSystemStartup.HandleServerIdent(Packet_Server packet) in VintagestoryLib\Client\Systems\Startup.cs:line 191
   at Vintagestory.Client.NoObf.ProcessPacketTask.ProcessPacket(Packet_Server packet) in VintagestoryLib\Client\Systems\ProcessPacketTask.cs:line 18
   at Vintagestory.Client.NoObf.ClientMain.ExecuteMainThreadTasks(Single deltaTime) in VintagestoryLib\Client\ClientMain.cs:line 786
   at Vintagestory.Client.NoObf.ClientMain.MainGameLoop(Single deltaTime) in VintagestoryLib\Client\ClientMain.cs:line 752
   at Vintagestory.Client.GuiScreenRunningGame.RenderToPrimary(Single dt) in VintagestoryLib\Client\MainMenu\Screens\GuiScreenRunningGame.cs:line 172
   at Vintagestory.Client.ScreenManager.Render(Single dt) in VintagestoryLib\Client\ScreenManager.cs:line 719
   at Vintagestory.Client.ScreenManager.OnNewFrame(Single dt) in VintagestoryLib\Client\ScreenManager.cs:line 663
   at Vintagestory.Client.NoObf.ClientPlatformWindows.window_RenderFrame(FrameEventArgs e) in VintagestoryLib\Client\ClientPlatform\GameWindow.cs:line 112
   at OpenTK.Windowing.Desktop.GameWindow.Run()
   at Vintagestory.Client.ClientProgram.Start(ClientProgramArgs args, String[] rawArgs) in VintagestoryLib\Client\ClientProgram.cs:line 338
   at Vintagestory.Client.ClientProgram.<>c__DisplayClass10_0.<.ctor>b__1() in VintagestoryLib\Client\ClientProgram.cs:line 133
   at Vintagestory.ClientNative.CrashReporter.Start(ThreadStart start) in VintagestoryLib\Client\ClientPlatform\ClientNative\CrashReporter.cs:line 95

[OleHooklip]

Adding some additional context, his game keeps mentioning an issue with a file called "openal32.dll."

All my research for crashes of that type suggest it has something to do with corrupted save files, but I don't see that being the case here, as this is an issue that prevents him from joining my server regardless of which save I load.

Again, any and all help is appreciated. We've tried reinstalling his game, we've tried reinstalling my game. Not sure what else we can do.

[OleHooklip]

Okay, wow, additional wrinkle. Here we go:

1. Tried sending friend my copy of the OpenAL32 file. Did not fix the issue.

2. Decided to delete my copy of OpenAL32. After deleting my OpenAL32 file while he keeps his copy of my OpenAL32 installed, he can now join my game. I am flabbergasted.

3. Friend tries to turn up graphics settings. He gets disconnected the second he turns the view distance above 32 blocks.

4. Perform testing to replicate this. He can play on the server just fine if his view distance is 64 blocks or lower, but any efforts to increase the view distance further result in him being immediately disconnected from the server.

5. Check his RAM utilization. Vintage Story is using less than half of his available RAM.

Utterly stumped at this point.

[Sparkplug04]

6 hours ago, OleHooklip said:

Okay, wow, additional wrinkle. Here we go:

1. Tried sending friend my copy of the OpenAL32 file. Did not fix the issue.

2. Decided to delete my copy of OpenAL32. After deleting my OpenAL32 file while he keeps his copy of my OpenAL32 installed, he can now join my game. I am flabbergasted.

3. Friend tries to turn up graphics settings. He gets disconnected the second he turns the view distance above 32 blocks.

4. Perform testing to replicate this. He can play on the server just fine if his view distance is 64 blocks or lower, but any efforts to increase the view distance further result in him being immediately disconnected from the server.

5. Check his RAM utilization. Vintage Story is using less than half of his available RAM.

Utterly stumped at this point.

That second point seems to be part of the issue. I presume you're hosting this on your machine?
Assuming that, it may be an issue of incompatibility. Different versions of OpenAL32, or yours could be damaged/corrupted which, being a DLL, could very easily explain this if it's the issue.
Not sure how you'd fix/replace that DLL personally, but it may be a starting point. It could also be dependent on operating system or graphical architecture (DirectX verison, other drivers, GPU hardware, etc.)

EDIT: Found a good starting point. Open command prompt, with Administrator privileges. Run the System File Checker with "sfc /scannow" on both computers.
SFC is a built-in recovery tool for DLLs and other critical Windows components, and it's quite reliable.
If that doesn't work, actually installing OpenAL or doing driver updates may be necessary. Or, a rollback on the driver version could be called for on your friend's machine.

There's a lot that may be going wrong here so it's hard to say, but trying these one step at a time and checking the progress should lead to success.

Edited October 12, 2025 by Sparkplug04
Found a possible repair option