Critical Bug – “Version Unknown” + Crash on Save (DX12) across ALL Twinmotion Versions

Title: Critical Bug – “Version Unknown” + Crash on Save (DX12) across ALL Twinmotion Versions

Hi everyone,

I’m facing a serious issue with Twinmotion and I want to know if anyone else is experiencing the same.


:red_circle: The Problem

I have multiple project files created in Twinmotion 2024 that were working perfectly before.

Now:

  • They do NOT open anymore

  • Twinmotion shows: “Version unknown”

  • Files have NOT been modified recently


:warning: It gets worse

In newer versions (2025 / 2026):

  • Sometimes the files do open

  • But when I try to save → Twinmotion crashes immediately

Error:
D3D12RHI / DirectX 12


:brain: What’s strange

  • Files from 2023 and older → open fine

  • New files → can open, but saving often crashes

  • After a crash → files become unreadable (“Version unknown”)


:laptop: System

  • GPU: RTX 5070 Laptop

  • OS: Windows 11

  • Drivers: NVIDIA Studio (also tested clean installs + older versions)

  • Device: ASUS ROG high-end laptop


:repeat_button: Versions tested

I tested ALL of these:

  • Twinmotion 2026.1 Preview

  • Twinmotion 2025.2

  • Twinmotion 2025.1.1

  • Twinmotion 2024.1.2

  • Twinmotion 2023

:backhand_index_pointing_right: Same behavior:

  • Either “Version unknown”

  • Or crash on save (DX12)


:hammer_and_wrench: What I already tried (everything)

  • Full clean reinstall (all versions)

  • Deleted all AppData + Unreal cache

  • Cleared logs / webcache / saved folders

  • Reinstalled Epic Games Launcher

  • Forced NVIDIA GPU (disabled integrated GPU)

  • Used DDU and installed different drivers

  • Installed all dependencies (VC++, DirectX, .NET)

  • Forced DX11 via Engine.ini

  • Switched GPU mode to Ultimate

  • Tested on another machine


:red_exclamation_mark: Conclusion

At this point, this does NOT look like a user issue.

It seems like:

  • A DX12 / GPU issue

  • Possibly related to RTX 50 series

  • Or a file parsing issue in newer builds


:folded_hands: Question

Is anyone else experiencing:

  • “Version unknown” on valid files?

  • Crashes when saving?

Would be great to know if this is widespread.

Thanks!

Had exactly the same issue. Works on Direct X11 but crashese every time I save using Direct X12