VS2015 - The 'NuGetPackage' package did not load correctly

Question

Just opened up VS 2015 Enterprise RTM, opened up an existing working project, getting the following error:

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Microsoft Visual Studio

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The 'NuGetPackage' package did not load correctly.

The problem may have been caused by a configuration change or by the installation of another extension. You can get more information by examining the file C:\Users\REDACTED\AppData\Roaming\Microsoft\VisualStudio\14.0\ActivityLog.xml.

Restarting Visual Studio could help resolve this issue.

Continue to show this error message?

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[Yes] [No]

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Restarting didn't help. I've examined the log file, and found the following sections relevant to nuget:

<entry>
  <record>555</record>
  <time>2015/07/20 16:06:34.364</time>
  <type>Error</type>
  <source>Extension Manager</source>
  <description>Extension will not be loaded because an extension with the same ID 
     &apos;Microsoft.Dev14.VsixTemplatesPackage.443cca91-ec20-41e5-a165-f28e56b89650&apos; 
     is already loaded at C:\PROGRAM FILES (X86)\MICROSOFT VISUAL STUDIO 14.0\COMMON7\IDE\
     EXTENSIONS\G2URSPAC.VAZ\...</description>
  <path>C:\PROGRAM FILES (X86)\MICROSOFT VISUAL STUDIO 14.0\COMMON7\IDE\EXTENSIONS\
     NUGETIFIEDEXTENSIBILITYTEMPLATES\</path>
</entry>
<entry>
  <record>556</record>
  <time>2015/07/20 16:06:34.364</time>
  <type>Error</type>
  <source>Extension Manager</source>
  <description>Extension will not be loaded because an extension with the same ID
     &apos;Microsoft.VisualStudio.TeamFoundation.TeamExplorer.Extensions&apos; is already
     loaded at C:\PROGRAM FILES (X86)\MICROSOFT VISUAL STUDIO 14.0\COMMON7\IDE\EXTENSIONS\
     B1NUOYPH.H2N\...</description>
  <path>C:\PROGRAM FILES (X86)\MICROSOFT VISUAL STUDIO 14.0\COMMON7\IDE\COMMONEXTENSIONS\
     MICROSOFT\TEAMFOUNDATION\TEAM EXPLORER\</path>
</entry>

Which would suggest a duplicate extension, but this doesn't seem to be the case in the extensions manager.

This is on a machine that also has VS2013 installed. It has not had any of the preview/RC builds of VS2015 installed ever.

Answer 1

Completely removing NuGet via Extensions and Updates, restarting VS then re-installing NuGet via Extensions and Updates solved the issue for me. A full VS reinstall was not necessary.

Answer 2

Updating Nuget to the latest version seems to have solved the problem.

1. Tools > Extensions and Updates

2. Updates > Visual Studio Gallery

3. Click Update on the Nuget Package Manager option