Could not find file DotNetOpenAuth.Core.dll

Error 1 Copying file bin\DotNetOpenAuth.Core.dll to obj\Release\Package\PackageTmp\bin\DotNetOpenAuth.Core.dll failed. Could not find file 'bin\DotNetOpenAuth.Core.dll'. 0 0 UKDJAgencyUmbraco You can fix this by downloading the package using nuget, or if you have already done that, have a look in the packages folder in your solution, this should have all the dlls you require, just make sure you use the correct dll for the relevant .net version you are working on.