Builds and Nuget Updates fails sporadically #52

Hi,
we experienced that builds can fail with the error message

The "PackageRetrievalTask" task failed unexpectedly.

The process cannot access the file 'D:\data\users\user\Documents\Project\Component\Solution\packages\packageX\packageX.nuspec' because it is being used by another process.

It is not always happening but happens sporadically.

Another thing we experience which may be linked to the same issue is, that updating Nuget packages which depend on baseclass/Contrib.Nuget fails and visual studio suggest a restart.

The error message is:

The process cannot access the file 'D:\data\users\user\Documents\Project\Component\Solution\packages\packageX\packageX.8.0.0-ci00252.nupkg' because it is being used by another process.

Can you provide a solution for this issue?