NuGet Warning NU1505

Scenario 1

Duplicate 'PackageDownload' items found. Remove the duplicate items or use the Update functionality to ensure a consistent restore behavior. The duplicate 'PackageDownload' items are: X [1.0.0], X [2.0.0].

Issue

Sometimes when adding PackageDownload items, you may end up adding an item for a particular package multiple times.

Example:

<ItemGroup>
  <PackageDownload Include="X" Version="[1.0.0]" />
</ItemGroup>
...
<!-- Somewhere else in the project file, or another MSBuild file-->
<ItemGroup>
  <PackageDownload Include="X" Version="[2.0.0]" />
</ItemGroup>

This can cause an inconsistent restore behavior.

Solution

Consult the recommendations in the warning message and do one of the following:

• Remove the duplicate items
• Use item Update instead of item Include