OpenRA

When I try to view a mission briefing from the game menu (single player), the game crashes.
There is an exception log. Anyone got a clue what to do ?
I am sorry if this has been posted already. Help would be much appreciated.

The exception log states the following:

OpenRA engine version release-20200503
Dune 2000 mod version release-20200503
on map 04557277dfe4804e40dc2632ca333bc297c9200e (D2k Shellmap by Westwood Studios, MustaphaTR).
Date: 2021-02-04 15:17:22Z
Operating System: Windows (Microsoft Windows NT 6.2.9200.0)
Runtime Version: .NET CLR 4.0.30319.42000
Exception of type `System.IO.EndOfStreamException`: Attempted to read past the end of the stream.
at OpenRA.StreamExts.ReadBytes(Stream s, Byte[] buffer, Int32 offset, Int32 count)
at OpenRA.StreamExts.ReadBytes(Stream s, Int32 count)
at OpenRA.StreamExts.ReadASCII(Stream s, Int32 length)
at OpenRA.Mods.Common.FileFormats.VqaReader..ctor(Stream stream)
at OpenRA.Mods.Common.Widgets.VqaPlayerWidget.Load(String filename)
at OpenRA.Mods.Common.Widgets.Logic.MissionBrowserLogic.PlayVideo(VqaPlayerWidget player, String video, PlayingVideo pv, Action onComplete)
at OpenRA.Mods.Common.Widgets.Logic.MissionBrowserLogic.<>c__DisplayClass26_0.<SelectMap>b__2()
at OpenRA.Mods.Common.Widgets.ButtonWidget.HandleMouseInput(MouseInput mi)
at OpenRA.Widgets.Widget.HandleMouseInputOuter(MouseInput mi)
at OpenRA.Widgets.Ui.HandleInput(MouseInput mi)
at OpenRA.DefaultInputHandler.<>c__DisplayClass5_0.<OnMouseInput>b__0()
at OpenRA.Sync.RunUnsynced[T](Boolean checkSyncHash, World world, Func`1 fn)
at OpenRA.Platforms.Default.Sdl2Input.PumpInput(Sdl2PlatformWindow device, IInputHandler inputHandler, Nullable`1 lockedMousePosition)
at OpenRA.Platforms.Default.Sdl2PlatformWindow.PumpInput(IInputHandler inputHandler)
at OpenRA.Renderer.EndFrame(IInputHandler inputHandler)
at OpenRA.Game.RenderTick()
at OpenRA.Game.Loop()
at OpenRA.Game.Run()
at OpenRA.Game.InitializeAndRun(String[] args)
at OpenRA.WindowsLauncher.RunGame(String[] args)

Does this happen for all missions, or only some?

Did you manually copy the vqa files from a gruntsmods install, or were these copied using the automatic installer?

I manually copied some files.
But it seems that this a bug that will be fixed in the future.
https://github.com/OpenRA/OpenRA/issues/19124

That bug is specific to the playtest, and doesn't happen on release-20200503.

Your issue happens when the 0-byte placeholder files (which aren't real videos) are manually copied from the gruntmods install. I believe that there is a separate file somewhere on the GruntMods website that has the real FMVs.