I have bug error status 0xc000012f

Hi i have problem can’t start unreal engine.
Error picture

For some reason the editor is complaining about your install of the Visual C++ Redistributable for Visual Studio 2015. Did you run into prerequisite related issues when installing the editor? I would start by downloading the Visual C++ Redistributable for Visual Studio 2015 from here: and seeing if it has a repair option.

If the repair fails, you could try a procedure similar to what Luos outlined in his answer but your fix should target the DLL called out in the error dialog. In this case it is VCRUNTIME140.dll. It would go something like this:

FIX VCRUNTIME140.dll

  • Download Visual C++ Redistributable for Visual Studio 2015 from here:
  • Find and backup your current C:\Windows\System32\VCRUNTIME140.dll. You can do this by renaming it to VCRUNTIME140.dll_BACKUP
  • Install the redist
  • Check to make sure you have a new VCRUNTIME140.dll

I have not seen that error code before but a quick internet search for 0xc000012f turns up a ton of hits which might be useful. Before using those, perhaps you could try the following:

FIX D3DCOMPILER_43.DLL

Download the Dx11 redist from here: Download DirectX End-User Runtimes (June 2010) from Official Microsoft Download Center

Find and backup your current C:\Windows\System32\D3DCOMPILER_43.dll. You can do this by renaming it to D3DCOMPILER_43.dll_BACKUP

Install the DirectX11 Redist.

Check to make sure you have a new D3DCOMPILER_43.DLL

Try running the launcher again.

Quoted from: Error d3dcompiler_43.dll error status 0xc000012f - Installation & Setup - Unreal Engine Forums