Shared error when opening Unity

[oxysoft]

2 errors pop out whenever Unity is first opened or the package is first added:

Failed to create DX11 vertex declaration; something wrong with vertex shader input data? (hr=80070057)

Shader error in 'DearImGui/Procedural': failed to open source file: 'Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl' at /Users/oxysoft/Repositories/Nanokin_Unity/Library/PackageCache/com.realgames.dear-imgui@561339c07f/Resources/Shaders/PassesUniversal.hlsl(4) (on d3d11)

Compiling Vertex program
Platform defines: UNITY_ENABLE_REFLECTION_BUFFERS UNITY_USE_DITHER_MASK_FOR_ALPHABLENDED_SHADOWS UNITY_PBS_USE_BRDF1 UNITY_SPECCUBE_BOX_PROJECTION UNITY_SPECCUBE_BLENDING UNITY_ENABLE_DETAIL_NORMALMAP SHADER_API_DESKTOP UNITY_LIGHT_PROBE_PROXY_VOLUME UNITY_LIGHTMAP_RGBM_ENCODING

We are on Unity 2019.3.14f1 using the legacy built-in render pipeline. Note this doesn't actually break anything, ImGui still works as expected in-game, so this is more an inconvenience.

[devnullicus]

You have to install the URP package to your project, though you don't actually need to USE it...