Are you using nuget.exe to generate packages, especially as part of your continuous integration? If you've upgraded to version 5.7, you may be experiencing unexpected errors like this:

Could not load file or assembly 'file:///C:\Program Files (x86)\NuGet CLI\nuget.exe' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)
Using '[project]].nuspec' for metadata.
Authors is required.
Description is required.

I've submitted a bug report which is slowly gaining traction, but to my knowledge isn't yet resolved. Here's a summary of the problem and conditions. Please follow the link for more details.


  • The [project].nuspec's token substitution isn't working, e.g. substituting AssemblyConfiguration for \(author\).
  • Applies to .Net Framework NuGet projects being packaged using nuget.exe


The error will occur under the following conditions

  • Version 5.6 is named nuget.5.6.exe. E.g. the command used is nuget.5.6 pack
  • Version 5.7 is named nuget.exe. E.g. the command used is nuget pack

You may get conflicting behaviors if:

  • You have both version 5.6 and 5.7 in your PATH


  • Use nuget.exe version 5.6.
  • Ensure only one nuget.exe version is in the PATH
  • Name the file nuget.exe