In recent days I’ve started having problems when trying to browse NuGet packages within VS2019 (e.g. by right-clicking a project -> Manage NuGet packages). I’ve no idea why this has started to happen all of a sudden, but this is what I see:-
The strange thing is, if I open the "Package Manager Console" window, it seems to give something a kick and the browse window starts working (although the problem returns when I restart VS). I’ve tried repairing VS but to no avail. Anyone else seen this, or have a more permanent fix?
Source: Visual Studio Questions