diff --git a/build/NuSpecs/UmbracoCms.Core.nuspec b/build/NuSpecs/UmbracoCms.Core.nuspec
index f67b85be28..7865c17d19 100644
--- a/build/NuSpecs/UmbracoCms.Core.nuspec
+++ b/build/NuSpecs/UmbracoCms.Core.nuspec
@@ -17,7 +17,6 @@
     <dependencies>
       <dependency id="Microsoft.AspNet.Mvc" version="[5.2.3,6.0.0)" />
       <dependency id="Microsoft.AspNet.WebApi" version="[5.2.3,6.0.0)" />
-      <dependency id="Microsoft.Net.Http" version="[2.2.29, 3.0.0)" />
       <dependency id="Microsoft.AspNet.Identity.Owin" version="[2.2.1, 3.0.0)" />
       <dependency id="Microsoft.Owin.Security.Cookies" version="[3.0.1, 4.0.0)" />
       <dependency id="Microsoft.Owin.Security.OAuth" version="[3.0.1, 4.0.0)" />
diff --git a/src/Umbraco.Core/Security/AuthenticationExtensions.cs b/src/Umbraco.Core/Security/AuthenticationExtensions.cs
index 79fdc1bed1..b8064474bb 100644
--- a/src/Umbraco.Core/Security/AuthenticationExtensions.cs
+++ b/src/Umbraco.Core/Security/AuthenticationExtensions.cs
@@ -167,74 +167,18 @@ namespace Umbraco.Core.Security
         /// This clears the forms authentication cookie for webapi since cookies are handled differently
         /// </summary>
         /// <param name="response"></param>
-        [Obsolete("Use OWIN IAuthenticationManager.SignOut instead")]
+        [Obsolete("Use OWIN IAuthenticationManager.SignOut instead", true)]
         [EditorBrowsable(EditorBrowsableState.Never)]
         public static void UmbracoLogoutWebApi(this HttpResponseMessage response)
         {
-            if (response == null) throw new ArgumentNullException("response");
-            //remove the cookie
-            var authCookie = new CookieHeaderValue(UmbracoConfig.For.UmbracoSettings().Security.AuthCookieName, "")
-            {
-                Expires = DateTime.Now.AddYears(-1),                
-                Path = "/"
-            };
-            //remove the preview cookie too
-            var prevCookie = new CookieHeaderValue(Constants.Web.PreviewCookieName, "")
-            {
-                Expires = DateTime.Now.AddYears(-1),
-                Path = "/"
-            };
-            //remove the external login cookie too
-            var extLoginCookie = new CookieHeaderValue(Constants.Security.BackOfficeExternalCookieName, "")
-            {
-                Expires = DateTime.Now.AddYears(-1),
-                Path = "/"
-            };
-
-            response.Headers.AddCookies(new[] { authCookie, prevCookie, extLoginCookie });
+            throw new NotSupportedException("This method is not supported and should not be used, it has been removed in Umbraco 7.4");
         }
 
-        [Obsolete("Use WebSecurity.SetPrincipalForRequest")]
+        [Obsolete("Use WebSecurity.SetPrincipalForRequest", true)]
         [EditorBrowsable(EditorBrowsableState.Never)]
         public static FormsAuthenticationTicket UmbracoLoginWebApi(this HttpResponseMessage response, IUser user)
         {
-            if (response == null) throw new ArgumentNullException("response");
-
-            //remove the external login cookie
-            var extLoginCookie = new CookieHeaderValue(Constants.Security.BackOfficeExternalCookieName, "")
-            {
-                Expires = DateTime.Now.AddYears(-1),
-                Path = "/"
-            };
-
-            var userDataString = JsonConvert.SerializeObject(Mapper.Map<UserData>(user));
-
-            var ticket = new FormsAuthenticationTicket(
-                4,
-                user.Username,
-                DateTime.Now,
-                DateTime.Now.AddMinutes(GlobalSettings.TimeOutInMinutes),
-                true,
-                userDataString,
-                "/"
-                );
-            
-            // Encrypt the cookie using the machine key for secure transport
-            var encrypted = FormsAuthentication.Encrypt(ticket);
-
-            //add the cookie
-            var authCookie = new CookieHeaderValue(UmbracoConfig.For.UmbracoSettings().Security.AuthCookieName, encrypted)
-            {
-                //Umbraco has always persisted it's original cookie for 1 day so we'll keep it that way
-                Expires = DateTime.Now.AddMinutes(1440),
-                Path = "/",
-                Secure = GlobalSettings.UseSSL,
-                HttpOnly = true
-            };
-
-            response.Headers.AddCookies(new[] { authCookie, extLoginCookie });
-
-            return ticket;
+            throw new NotSupportedException("This method is not supported and should not be used, it has been removed in Umbraco 7.4");            
         }
 
         /// <summary>
diff --git a/src/Umbraco.Core/Services/EntityXmlSerializer.cs b/src/Umbraco.Core/Services/EntityXmlSerializer.cs
index 69c6708496..00bc7c5a9b 100644
--- a/src/Umbraco.Core/Services/EntityXmlSerializer.cs
+++ b/src/Umbraco.Core/Services/EntityXmlSerializer.cs
@@ -2,7 +2,6 @@ using System;
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
-using System.Net.Http.Formatting;
 using System.Web;
 using System.Xml;
 using System.Xml.Linq;
diff --git a/src/Umbraco.Core/Umbraco.Core.csproj b/src/Umbraco.Core/Umbraco.Core.csproj
index cee2f8ee3f..03114ed0f1 100644
--- a/src/Umbraco.Core/Umbraco.Core.csproj
+++ b/src/Umbraco.Core/Umbraco.Core.csproj
@@ -112,18 +112,6 @@
     </Reference>
     <Reference Include="System.Drawing" />
     <Reference Include="System.Net.Http" />
-    <Reference Include="System.Net.Http.Extensions, Version=2.2.29.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <HintPath>..\packages\Microsoft.Net.Http.2.2.29\lib\net45\System.Net.Http.Extensions.dll</HintPath>
-      <Private>True</Private>
-    </Reference>
-    <Reference Include="System.Net.Http.Formatting, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL">
-      <HintPath>..\packages\Microsoft.AspNet.WebApi.Client.4.0.30506.0\lib\net40\System.Net.Http.Formatting.dll</HintPath>
-      <SpecificVersion>False</SpecificVersion>
-    </Reference>
-    <Reference Include="System.Net.Http.Primitives, Version=4.2.29.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <HintPath>..\packages\Microsoft.Net.Http.2.2.29\lib\net45\System.Net.Http.Primitives.dll</HintPath>
-      <Private>True</Private>
-    </Reference>
     <Reference Include="System.Net.Http.WebRequest" />
     <Reference Include="System.Runtime.Caching" />
     <Reference Include="System.Runtime.Serialization" />
@@ -1414,7 +1402,9 @@
   <ItemGroup>
     <None Include="app.config" />
     <None Include="FileResources\BlockingWeb.config" />
-    <None Include="packages.config" />
+    <None Include="packages.config">
+      <SubType>Designer</SubType>
+    </None>
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\umbraco.interfaces\umbraco.interfaces.csproj">
@@ -1430,11 +1420,6 @@
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <Import Project="$(SolutionDir)\.nuget\nuget.targets" />
-  <Import Project="..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets" Condition="Exists('..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets')" />
-  <Target Name="EnsureBclBuildImported" BeforeTargets="BeforeBuild" Condition="'$(BclBuildImported)' == ''">
-    <Error Condition="!Exists('..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets')" Text="This project references NuGet package(s) that are missing on this computer. Enable NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=317567." HelpKeyword="BCLBUILD2001" />
-    <Error Condition="Exists('..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets')" Text="The build restored NuGet packages. Build the project again to include these packages in the build. For more information, see http://go.microsoft.com/fwlink/?LinkID=317568." HelpKeyword="BCLBUILD2002" />
-  </Target>
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
   <Target Name="BeforeBuild">
diff --git a/src/Umbraco.Core/packages.config b/src/Umbraco.Core/packages.config
index 4ab720b7be..f41fc85c81 100644
--- a/src/Umbraco.Core/packages.config
+++ b/src/Umbraco.Core/packages.config
@@ -5,10 +5,6 @@
   <package id="log4net-mediumtrust" version="2.0.0" targetFramework="net4" />
   <package id="Microsoft.AspNet.Identity.Core" version="2.2.1" targetFramework="net45" />
   <package id="Microsoft.AspNet.Identity.Owin" version="2.2.1" targetFramework="net45" />
-  <package id="Microsoft.AspNet.WebApi.Client" version="4.0.30506.0" targetFramework="net45" />
-  <package id="Microsoft.Bcl" version="1.1.10" targetFramework="net45" />
-  <package id="Microsoft.Bcl.Build" version="1.0.14" targetFramework="net45" />
-  <package id="Microsoft.Net.Http" version="2.2.29" targetFramework="net45" />
   <package id="Microsoft.Owin" version="3.0.1" targetFramework="net45" />
   <package id="Microsoft.Owin.Security" version="3.0.1" targetFramework="net45" />
   <package id="Microsoft.Owin.Security.Cookies" version="3.0.1" targetFramework="net45" />
diff --git a/src/Umbraco.Web.UI/Umbraco.Web.UI.csproj b/src/Umbraco.Web.UI/Umbraco.Web.UI.csproj
index 6993b7cad9..60f4d19130 100644
--- a/src/Umbraco.Web.UI/Umbraco.Web.UI.csproj
+++ b/src/Umbraco.Web.UI/Umbraco.Web.UI.csproj
@@ -2458,9 +2458,4 @@ xcopy "$(ProjectDir)"..\packages\SqlServerCE.4.0.0.0\x86\*.* "$(TargetDir)x86\"
     </ReadLinesFromFile>
     <Exec WorkingDirectory="$(ProjectDir)\..\..\build\" Command="BuildBelle.bat $(VersionNumber)" ConsoleToMSBuild="true" IgnoreExitCode="true" ContinueOnError="WarnAndContinue" />
   </Target>
-  <Import Project="..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets" Condition="Exists('..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets')" />
-  <Target Name="EnsureBclBuildImported" BeforeTargets="BeforeBuild" Condition="'$(BclBuildImported)' == ''">
-    <Error Condition="!Exists('..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets')" Text="This project references NuGet package(s) that are missing on this computer. Enable NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=317567." HelpKeyword="BCLBUILD2001" />
-    <Error Condition="Exists('..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets')" Text="The build restored NuGet packages. Build the project again to include these packages in the build. For more information, see http://go.microsoft.com/fwlink/?LinkID=317568." HelpKeyword="BCLBUILD2002" />
-  </Target>
 </Project>
\ No newline at end of file
diff --git a/src/Umbraco.Web.UI/packages.config b/src/Umbraco.Web.UI/packages.config
index 5d0ad917f4..e091178201 100644
--- a/src/Umbraco.Web.UI/packages.config
+++ b/src/Umbraco.Web.UI/packages.config
@@ -18,8 +18,6 @@
   <package id="Microsoft.AspNet.WebApi.Core" version="5.2.3" targetFramework="net45" />
   <package id="Microsoft.AspNet.WebApi.WebHost" version="5.2.3" targetFramework="net45" />
   <package id="Microsoft.AspNet.WebPages" version="3.2.3" targetFramework="net45" />
-  <package id="Microsoft.Bcl" version="1.1.9" targetFramework="net45" />
-  <package id="Microsoft.Bcl.Build" version="1.0.14" targetFramework="net45" />
   <package id="Microsoft.CodeAnalysis.Analyzers" version="1.0.0" targetFramework="net45" />
   <package id="Microsoft.CodeAnalysis.Common" version="1.0.0" targetFramework="net45" />
   <package id="Microsoft.CodeAnalysis.CSharp" version="1.0.0" targetFramework="net45" />
diff --git a/src/Umbraco.Web/WebApi/Filters/UmbracoBackOfficeLogoutAttribute.cs b/src/Umbraco.Web/WebApi/Filters/UmbracoBackOfficeLogoutAttribute.cs
index 8912ca68ca..c42881f52a 100644
--- a/src/Umbraco.Web/WebApi/Filters/UmbracoBackOfficeLogoutAttribute.cs
+++ b/src/Umbraco.Web/WebApi/Filters/UmbracoBackOfficeLogoutAttribute.cs
@@ -5,23 +5,13 @@ using Umbraco.Core.Security;
 
 namespace Umbraco.Web.WebApi.Filters
 {
-    [Obsolete("This is no longer used and will be removed from the codebase in the future, use OWIN IAuthenticationManager.SignOut instead")]
+    [Obsolete("This is no longer used and will be removed from the codebase in the future, use OWIN IAuthenticationManager.SignOut instead", true)]
     [EditorBrowsable(EditorBrowsableState.Never)]
     public sealed class UmbracoBackOfficeLogoutAttribute : ActionFilterAttribute
     {
         public override void OnActionExecuted(HttpActionExecutedContext context)
-        {            
-            if (context.Response == null) return;
-            if (context.Response.IsSuccessStatusCode == false) return;
-
-            //this clears out all of our cookies
-            context.Response.UmbracoLogoutWebApi();
-            
-            //this calls the underlying owin sign out logic - which should call the 
-            // auth providers middleware callbacks if using custom auth middleware
-            context.Request.TryGetOwinContext().Result.Authentication.SignOut(
-                Core.Constants.Security.BackOfficeAuthenticationType,
-                Core.Constants.Security.BackOfficeExternalAuthenticationType);
+        {
+            throw new NotSupportedException("This method is not supported and should not be used, it has been removed in Umbraco 7.4");
         }
     }
 }
\ No newline at end of file