(In reply to MC Return from comment #8)
> GLShader::loadFragment(): error in
> "core/shaders/render/fragment_occlusion_blur.shader" file
> defines:
> UNKNOWN,QUALITY_LOW,QUALITY_MEDIUM,QUALITY_HIGH,MULTISAMPLE_0,USE_INSTANCING,
> USE_TEXTURE_ARRAY,USE_DEFERRED,USE_TRANSLUCENT,USE_PARALLAX,USE_OCCLUSION,
> USE_REFLECTION,OPENGL,USE_PSEUDO_INSTANCING,USE_PSEUDO_TRANSFORM,
> USE_ARB_SAMPLE_SHADING,USE_ARB_TEXTURE_MULTISAMPLE,HAS_ARB_DRAW_INSTANCED
> 0:511(15): error: no function with name 'texelFetch2DOffset'

These errors may indicate that it's not picking up the correct drirc
configuration. Does it work if you set the following environment variables for
running it:

LIBGL_DEBUG=verbose force_glsl_extensions_warn=true
disable_blend_func_extended=true

If not, please provide the corresponding terminal output and log file again.