AAPT: Unknown option '--no-version-vectors'

If you ever encountered the error AAPT: Unknown option '--no-version-vectors' during the Xamarin build you probably found this page looking for a solution. Like I did. Then you probably first tried setting AndroidSdkBuildToolsVersion to the latest you have. Just like me. Or uninstall all the older versions. If this didn’t work (like in my case) stay with me.

The suggestion of changing the build tools version in Droid csproj didn’t even look promising for me. I had only one version installed - 25.0.3 - and this was the latest one (at the time I’m writing this post). Nevertheless I checked this out, just in case, as this was the accepted solution in this thread. The error did not disappear.

I find a reasonable level of laziness practical. In fact this is usually a motivation for me to automate things. And it often pays off. Unfortunately not this time. As a typical lazy developer I skipped the rest of the discussion in the forum thread and started digging on my own. After a wasted hour I got back to the thread and found out that the build version tools solution didn’t work for others as well. Importantly one of later posts was pointing the solution.

True reason was the duplicated MSBuild target imports in csproj file:

<Import Project="..\packages\Xamarin.Android.Support.Vector.Drawable.25.1.0\build\MonoAndroid70\Xamarin.Android.Support.Vector.Drawable.targets" Condition="Exists('..\packages\Xamarin.Android.Support.Vector.Drawable.25.1.0\build\MonoAndroid70\Xamarin.Android.Support.Vector.Drawable.targets')" />
<Import Project="..\packages\Xamarin.Android.Support.Animated.Vector.Drawable.25.1.0\build\MonoAndroid70\Xamarin.Android.Support.Animated.Vector.Drawable.targets" Condition="Exists('..\packages\Xamarin.Android.Support.Animated.Vector.Drawable.25.1.0\build\MonoAndroid70\Xamarin.Android.Support.Animated.Vector.Drawable.targets')" />
...
<Import Project="..\packages\Xamarin.Android.Support.Vector.Drawable.25.1.1\build\MonoAndroid70\Xamarin.Android.Support.Vector.Drawable.targets" />
<Import Project="..\packages\Xamarin.Android.Support.Animated.Vector.Drawable.25.1.1\build\MonoAndroid70\Xamarin.Android.Support.Animated.Vector.Drawable.targets" />

This was probably caused by NuGet package manager (rather the clone used in Xamarin Studio or JetBrain’s Rider I’m using).

Lesson learned - RTFM ;-) And don’t be too lazy, as I am.

Happy coding!