I am unable to either fresh install 10.0.2 or upgrade from 10.0.1. The error I always get is tons like this one, where it clearly can't access the folders.
Packages directory here \Newtonsoft.Json.10.0.2\lib\net20\Newtonsoft.Json.xml could not be found in your workspace, or you do not have permission to access it.
If I check the packages directory I indeed only have a 10.0.1 folder, even with fresh install.
Edit: If I open a explorer window in the directory, and constantly hit F5 during "upgrade", I can see that a 10.0.2 folder gets created. It gets deleted as soon as the upgrade fails.
Edit2: could this be related to TFS somehow?