Hi hulluperuna,
Thank you for contacting Syncfusion Support.
This Error is common when we use multiple Xamarin.Forms Package in our samples. To avoid this error being occurred in your project, please follow the below given procedure.
Check whether Xamarin.Forms package has been included with the same version in all projects. If not add same version of Xamarin.Forms package
Even after changing the Version of Xamarin.Forms does not resolve this error please follow the below given steps.
1. Remove the Xamarin.Forms package from your project (It includes PCL, Xamain.Forms.Android, Xamain.Forms.iOS and Xamain.Forms.UWP)
2. Now add the appropriate version of Xamarin.Forms into your project and build it.
Also we have prepared a sample, in which the SfNavigationDrawer works with the latest Xamarin.Forms package.
Sample link:
http://www.syncfusion.com/downloads/support/directtrac/general/ze/NavigationDrawerGettingStarted_51630602687.zip Please let us know if you have any concern about this.
Regards,
Selva Kumar V.