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

Development Architectural and Design Visualization
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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!

2

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

3

Yes, exactly the same here.

DX11 seems more stable, but DX12 causes crashes when saving and also leads to “version unknown” issues on files.

I’ve tested multiple versions (2024, 2025, 2026) and the behavior is consistent.

This looks like a serious DX12-related issue, especially on newer GPUs.

Thanks for confirming.