Downloading IntelliSense index for nuget.org

I've recently updated my Visual Studio IDE from v.2017 to v.2019.

Since then, a background task was permantly running under the label "Downloading IntelliSense index for nuget.org".

A few entries appear googling the issue, and the official answer always is "update to the latest version and try again". And obviously, that doesn't work. 

Then, I've found this entry from Lars Wilhelmsen:

Create an DWORD (32-bit) value called Enabled and set it to 0 under:

HKCU\SOFTWARE\Microsoft\VisualStudio\16.0_6cf1d688\Roslyn\Features\SymbolSearch

The 'Roslyn\Features\SymbolSearch' keys have to be created as well. The '16.0_6cf1d688' version number might be different on your machine.

And magically, the problem is solved.