# Why am I receiving the "System.DllNotFoundException: …" error in my ODA .NET app, even though I have put the specified DLL in the output folder?

 1. [FAQ](/faq)
2. »
3. [Build issues](/faq/build-issues)

Most likely, this is happening because of missing C++ libraries from the output folder: as our .NET SDKs are only wrappers over our C++ ones, all the required native libraries should be available to .NET application too. This applies to all of our SDKs.

Most of the original C++ libraries are presented as separate .NET DLLs: FacetModeler\_{version}.dll -> OdSwig\_FacetModeler\_Mgd.dll  
However, there are two exceptions: TD\_RootIntegrated and TD\_DbCoreIntegrated, which contain combined APIs from several C++ modules.

Core C++ libraries are specified in the "Core components" section in "Determining which Libraries to Use" documentation page: https://docs.opendesign.com/td/tdrawings\_libraries.html.