onnxruntime: Unable to load DLL 'onnxruntime.dll': The specified module could not be found.

Describe the bug After installing Nuget package and attempting to create a session I get the following error in a WinForms app on .NET Framework version 4.6.1:

Unable to load DLL 'onnxruntime.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)

at line 33 in Microsoft.ML.OnnxRuntime.SessionOptions:

public SessionOptions()
{
     _nativeOption = new NativeOnnxObjectHandle(NativeMethods.ONNXRuntimeCreateSessionOptions());
}

System information

OS Platform and Distribution (e.g., Linux Ubuntu 16.04): Windows
ONNX Runtime installed from (source or binary): Nuget Installed Microsoft.ML.OnnxRuntime in VS17
ONNX Runtime version: 0.1.5

To Reproduce Added Nuget package and attempted the following code with a valid onnx file:

var options = SessionOptions.Default;
options.AppendExecutionProvider(ExecutionProvider.Cpu);
_session = new InferenceSession(file, options);

I tried running from Visual Studio on x64

Expected behavior The dll should load and the session should start.

Note I am sure this is a silly error on my part but maybe others will run into it.

About this issue

Original URL
State: closed
Created 6 years ago
Reactions: 6
Comments: 28 (7 by maintainers)

Most upvoted comments

I don’t understand why this is closed. Shouldn’t the nuget package copy the native file automatically?

+17

n8allan on Mar 30, 2019

I struggled with this until I fired up “Depends” and discovered that it requires the VC runtime.

n8allan on Sep 25, 2020

Having the same issue using AnyCPU - It doesn’t download/install the 32bit DLLs and so the project I’m trying to use it fails with System.BadImageFormatException: 'Could not load file or assembly 'Aspose.OCR, Version=21.1.2.0, Culture=neutral, PublicKeyToken=716fcc553a201e56' or one of its dependencies. An attempt was made to load a program with an incorrect format.' (because it loads the 64 bit DLLs)

I downloaded the x86 release zip and was able to place onnxruntime.dll in the right directory (\packages\Microsoft.ML.OnnxRuntime.MKLML.1.4.0\runtimes\win-x86\native\) to (assumedly, since I can’t run it) fix it, but I’m not able to find pre-compiled x86 versions of mklml.dll and libiomp5md.dll to see if this would fix it for them as well.

I did some digging to see if I could find a solution to your issue but was unable to locate any x86 binaries. I think your best bet might be to download the source code from Microsoft.ML source code and try to build your desired x86 libs.

Keep in mind not all functionalities when running x86 are supported, specifically TensorFlow and LightGBM. This is stated in the github for ML. Another reference to x86 not being supported here. Who knows what issues might arise when trying to build the lib with your setup so I would suggest migrating your project to x64 if possible.

Chase-William on Feb 19, 2021

i’m having the same issue on 1.4.2 any suggestion ?

System.TypeInitializationException: The type initializer for ‘Microsoft.ML.OnnxR untime.NativeMethods’ threw an exception. —> System.DllNotFoundException: Unable to load DLL ‘onnxruntime’ or one of it s dependencies: The specified module could not be found. (0x8007007E) at Microsoft.ML.OnnxRuntime.NativeMethods.OrtGetApiBase() at Microsoft.ML.OnnxRuntime.NativeMethods…cctor() — End of inner exception stack trace — at Microsoft.ML.OnnxRuntime.SessionOptions…ctor() at Microsoft.ML.OnnxRuntime.InferenceSession…ctor(String modelPath) at Microsoft.ML.Transforms.Onnx.OnnxModel…ctor(String modelFile, Nullable1 gpuDeviceId, Boolean fallbackToCpu, Boolean ownModelFile, IDictionary2 shapeDic tionary)

OS Platform: Windows 7 64bit ONNX Runtime installed from Nuget Microsoft.ML.OnnxRuntime in VS19 ONNX Runtime version: 1.4.2

devnet123 on Sep 23, 2020

I’ve had similar problems with onnxruntime.dll when deploying my application on other computers.

In the end it came down to installing “Visual C++ Redistributable for Visual Studio” (VC_redist.x64.exe & VC_redist.x86.exe). After installing these libraries the problem was resolved and onnxruntime.dll loaded without problems.

nelemans1971 on Feb 10, 2021

I was facing this issue (or possibly a similar issue), and I ended up installing https://www.nuget.org/packages/Microsoft.ML.OnnxRuntime/1.5.2?_src=template which resolved the issue for me.

Grayda on Nov 30, 2020