Can you please take a look at the workaround here on NuGet known issues page: http://docs.nuget.org/docs/reference/known-issues#Upgrading_to_latest_NuGet_from_an_older_version_causes_a_signature_verification_error.
Cant install update because of singnature issues. Is there a resolution to this?
3/14/2013 1:05:07 PM - Install Error : VSIXInstaller.SignatureMismatchException: The installed version of 'NuGet Package Manager' is signed, but the update version has an invalid signature. Therefore, Extension Manager cannot install the update.
After reading some of the reviews here I decided not to chance any install of this file, I do enough configuring, don't want to cause myself problems over a database view, so I sought for an answer elsewhere. Here it is: