NuGet Error NU5042 (Obsolete)

Warning

project.json support has been removed starting with NuGet 7.0 and this error will no longer be raised.

project.json pack is disabled in the current NuGet version, and will be permanently removed in a future version. Please consider migrating 'MyProject' to PackageReference and using the pack targets. You can set the 'NUGET_ENABLE_LEGACY_PROJECT_JSON_PACK' environment variable to 'true' to temporarily reenable this functionality.

Issue

NuGet.exe pack for project.json projects is not supported.

Solution

Migrate your project to PackageReference and use the pack targets instead.