I have a problem with the update Microsoft.NETCore.UniversalWindowsPlatform.
There was version 5.0.0, when you start the development environment, the management offered me
For this error like the following screen shot, two suggestions:
(1)Tools > Options > Projects and Solutions > General, please checked "Save new projects when created" option.
(2)Install the latest packages:
Install-Package Microsoft.NETCore.UniversalWindowsPlatform
https://www.nuget.org/packages/Microsoft.NETCore.UniversalWindowsPlatform/5.2.2