.NET SDK 4.3.0 does not build for Windows Phone

Hi. I have a Windows Phone 8.1 app. After updating to the latest Dropbox SDK, the build now fails at the deploy stage where it is generating the MDIL. The CrossGen seems to be failing. I have tried cleaning and deleting the obj and bin folders with no success. The relevant lines from the MDILXapCompileLog.txt are pasted below. I need to update this app to deal with the bug in the previous SDK, which may start to manifest itselft in a couple of weeks...

Processing file: C:\Users\mark_\Documents\Apps\MyApp\MyApp.WindowsPhone\obj\ARM\Debug\MSIL\Dropbox.Api.dll
Calling CrossGen with arguments:
/nologo /mdil /MissingDependenciesOK /fulltrust  /app_paths "C:\Users\mark_\Documents\Apps\MyApp\MyApp.WindowsPhone\obj\ARM\Debug\MSIL;"  /trusted_platform_assemblies "C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\Internal.Numerics.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\Microsoft.CSharp.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\Microsoft.VisualBasic.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\mscorlib.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\mscorlib.extensions.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Collections.Concurrent.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Collections.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.ComponentModel.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.ComponentModel.EventBasedAsync.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Core.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Diagnostics.Contracts.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Diagnostics.Debug.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Diagnostics.Tools.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Diagnostics.Tracing.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Dynamic.Runtime.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Globalization.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.IO.Compression.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.IO.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Linq.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Linq.Expressions.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Linq.Parallel.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Linq.Queryable.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Net.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Net.Http.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Net.Http.Phone.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Net.Http.Primitives.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Net.NetworkInformation.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Net.Primitives.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Net.Requests.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.ObjectModel.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Reflection.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Reflection.Extensions.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Reflection.Primitives.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Resources.ResourceManager.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Runtime.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Runtime.Extensions.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Runtime.InteropServices.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Runtime.InteropServices.WindowsRuntime.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Runtime.Numerics.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Runtime.Serialization.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Runtime.Serialization.Json.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Runtime.Serialization.Primitives.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Runtime.Serialization.Xml.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Runtime.WindowsRuntime.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Runtime.WindowsRuntime.UI.Xaml.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Security.Principal.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.ServiceModel.Web.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Text.Encoding.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Text.Encoding.Extensions.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Text.RegularExpressions.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Threading.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Threading.Tasks.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Threading.Tasks.Parallel.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Threading.Timer.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Xml.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Xml.Linq.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Xml.ReaderWriter.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Xml.Serialization.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Xml.XDocument.dll;C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\Framework\System.Xml.XmlSerializer.dll;"  /platform_winmd_paths "C:\Program Files (x86)\Microsoft SDKs\WindowsPhoneApp\v8.1\Tools\MDILXAPCompile\WinMDs;"  /out "C:\Users\mark_\Documents\Apps\MyApp\MyApp.WindowsPhone\obj\ARM\Debug\MDIL\Dropbox.Api.dll" "C:\Users\mark_\Documents\Apps\MyApp\MyApp.WindowsPhone\obj\ARM\Debug\MSIL\Dropbox.Api.dll"
Output:


CrossGen failed
Error processing assembly C:\Users\mark_\Documents\Apps\MyApp\MyApp.WindowsPhone\obj\ARM\Debug\MSIL\Dropbox.Api.dll
Raw error code: 3221226505