For x64 builds we call the enhancer.exe explicitly by specifying the required parameters. There seems to be a problem with a long parameter value for the '-reference' parameter.
As a workaround you need to add the following property to the project file for the assembly that is being enhanced. You can add it after the 'EnhancerAssembly' property. This will avoid the command line parameter value from being too long.
<ReferencesArgs> "-reference:$(SolutionDir)\packages\Telerik.DataAccess.Core.2016.1.224.1\lib\net40\Telerik.OpenAccess.35.Extensions.dll" "-reference: (add your references)</ReferencesArgs>
You should add all the required assembly references.
Do get back in case you need further assistance.
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