diff --git a/fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj b/fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj
index d6c71b55456..6ee0cfab376 100644
--- a/fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj
+++ b/fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj
@@ -101,5 +101,6 @@
     <Reference Include="UIAutomationTypes" />
     <ProjectReference Include="CSharp_Analysis\CSharp_Analysis.csproj" />
     <ProjectReference Include="..\FSharp.Compiler.Service.ProjectCracker\FSharp.Compiler.Service.ProjectCracker.fsproj" />
+    <ProjectReference Include="$(FSharpSourcesRoot)\fsharp\FSharp.Compiler.Interactive.Settings\FSharp.Compiler.Interactive.Settings.fsproj" />
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/src/fsharp/CompileOps.fs b/src/fsharp/CompileOps.fs
index 69f83055562..22e5923374e 100644
--- a/src/fsharp/CompileOps.fs
+++ b/src/fsharp/CompileOps.fs
@@ -2321,6 +2321,7 @@ type TcConfigBuilder =
             isInvalidationSupported = isInvalidationSupported
             copyFSharpCore = defaultCopyFSharpCore
             tryGetMetadataSnapshot = tryGetMetadataSnapshot
+            useFsiAuxLib = isInteractive
         }
 
     member tcConfigB.ResolveSourceFile(m, nm, pathLoadedFrom) = 
diff --git a/src/fsharp/service/FSharpCheckerResults.fs b/src/fsharp/service/FSharpCheckerResults.fs
index ab8ee3d216f..cd9b187d3ad 100644
--- a/src/fsharp/service/FSharpCheckerResults.fs
+++ b/src/fsharp/service/FSharpCheckerResults.fs
@@ -58,7 +58,7 @@ module internal FSharpCheckerResultsSettings =
         | s -> int64 s
 
     // Look for DLLs in the location of the service DLL first.
-    let defaultFSharpBinariesDir = FSharpEnvironment.BinFolderOfDefaultFSharpCompiler(Some(typeof<IncrementalBuilder>.Assembly.Location)).Value
+    let defaultFSharpBinariesDir = FSharpEnvironment.BinFolderOfDefaultFSharpCompiler(Some(Path.GetDirectoryName(typeof<IncrementalBuilder>.Assembly.Location))).Value
 
 [<RequireQualifiedAccess>]
 type FSharpFindDeclFailureReason = 
diff --git a/src/fsharp/service/IncrementalBuild.fs b/src/fsharp/service/IncrementalBuild.fs
index 4cb4c23ea4a..365570b5d62 100755
--- a/src/fsharp/service/IncrementalBuild.fs
+++ b/src/fsharp/service/IncrementalBuild.fs
@@ -1732,7 +1732,7 @@ type IncrementalBuilder(tcGlobals, frameworkTcImports, nonFrameworkAssemblyInput
                          defaultFSharpBinariesDir, 
                          implicitIncludeDir=projectDirectory, 
                          reduceMemoryUsage=ReduceMemoryFlag.Yes, 
-                         isInteractive=false, 
+                         isInteractive=useScriptResolutionRules, 
                          isInvalidationSupported=true, 
                          defaultCopyFSharpCore=CopyFSharpCoreFlag.No, 
                          tryGetMetadataSnapshot=tryGetMetadataSnapshot) 
diff --git a/vsintegration/tests/UnitTests/FsxCompletionProviderTests.fs b/vsintegration/tests/UnitTests/FsxCompletionProviderTests.fs
new file mode 100644
index 00000000000..468c916dc95
--- /dev/null
+++ b/vsintegration/tests/UnitTests/FsxCompletionProviderTests.fs
@@ -0,0 +1,161 @@
+// To run the tests in this file:
+//
+// Technique 1: Compile VisualFSharp.UnitTests.dll and run it as a set of unit tests
+//
+// Technique 2:
+//
+//   Enable some tests in the #if EXE section at the end of the file, 
+//   then compile this file as an EXE that has InternalsVisibleTo access into the
+//   appropriate DLLs.  This can be the quickest way to get turnaround on updating the tests
+//   and capturing large amounts of structured output.
+(*
+    cd Debug\net40\bin
+    .\fsc.exe --define:EXE -r:.\Microsoft.Build.Utilities.Core.dll -o VisualFSharp.UnitTests.exe -g --optimize- -r .\FSharp.Compiler.Private.dll  -r .\FSharp.Editor.dll -r nunit.framework.dll ..\..\..\tests\service\FsUnit.fs ..\..\..\tests\service\Common.fs /delaysign /keyfile:..\..\..\src\fsharp\msft.pubkey ..\..\..\vsintegration\tests\UnitTests\FsxCompletionProviderTests.fs 
+    .\VisualFSharp.UnitTests.exe 
+*)
+// Technique 3: 
+// 
+//    Use F# Interactive.  This only works for FSharp.Compiler.Service.dll which has a public API
+
+// Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.
+namespace Microsoft.VisualStudio.FSharp.Editor.Tests.Roslyn
+
+open System
+open System.Collections.Generic
+open System.IO
+open System.Linq
+open System.Reflection
+
+open NUnit.Framework
+
+open Microsoft.CodeAnalysis
+open Microsoft.CodeAnalysis.Completion
+open Microsoft.CodeAnalysis.Text
+open Microsoft.VisualStudio.FSharp.Editor
+
+open FSharp.Compiler.SourceCodeServices
+open UnitTests.TestLib.LanguageService
+
+// AppDomain helper
+type Worker () =
+    inherit MarshalByRefObject()
+                            
+    let filePath = "C:\\test.fsx"
+    let projectOptions = { 
+        ProjectFileName = "C:\\test.fsproj"
+        ProjectId = None
+        SourceFiles =  [| filePath |]
+        ReferencedProjects = [| |]
+        OtherOptions = [| |]
+        IsIncompleteTypeCheckEnvironment = true
+        UseScriptResolutionRules = true
+        LoadTime = DateTime.MaxValue
+        OriginalLoadReferences = []
+        UnresolvedReferences = None
+        ExtraProjectInfo = None
+        Stamp = None
+    }
+
+    let formatCompletions(completions : string seq) =
+        "\n\t" + String.Join("\n\t", completions)
+
+    let VerifyCompletionList(fileContents: string, marker: string, expected: string list, unexpected: string list) =
+        let caretPosition = fileContents.IndexOf(marker) + marker.Length
+        let results = 
+            FSharpCompletionProvider.ProvideCompletionsAsyncAux(checker, SourceText.From(fileContents), caretPosition, projectOptions, filePath, 0, (fun _ -> []), LanguageServicePerformanceOptions.Default, IntelliSenseOptions.Default) 
+            |> Async.RunSynchronously 
+            |> Option.defaultValue (ResizeArray())
+            |> Seq.map(fun result -> result.DisplayText)
+
+        let expectedFound =
+            expected
+            |> Seq.filter results.Contains
+
+        let expectedNotFound =
+            expected
+            |> Seq.filter (expectedFound.Contains >> not)
+
+        let unexpectedNotFound =
+            unexpected
+            |> Seq.filter (results.Contains >> not)
+
+        let unexpectedFound =
+            unexpected
+            |> Seq.filter (unexpectedNotFound.Contains >> not)
+
+        // If either of these are true, then the test fails.
+        let hasExpectedNotFound = not (Seq.isEmpty expectedNotFound)
+        let hasUnexpectedFound = not (Seq.isEmpty unexpectedFound)
+
+        if hasExpectedNotFound || hasUnexpectedFound then
+            let expectedNotFoundMsg = 
+                if hasExpectedNotFound then
+                    sprintf "\nExpected completions not found:%s\n" (formatCompletions expectedNotFound)
+                else
+                    String.Empty
+
+            let unexpectedFoundMsg = 
+                if hasUnexpectedFound then
+                    sprintf "\nUnexpected completions found:%s\n" (formatCompletions unexpectedFound)
+                else
+                    String.Empty
+
+            let completionsMsg = sprintf "\nin Completions:%s" (formatCompletions results)
+
+            let msg = sprintf "%s%s%s" expectedNotFoundMsg unexpectedFoundMsg completionsMsg
+
+            Assert.Fail(msg)
+
+    member __.VerifyCompletionListExactly(fileContents: string, marker: string, expected: List<string>) =
+
+        let caretPosition = fileContents.IndexOf(marker) + marker.Length
+        let expected = expected |> Seq.toList
+        let actual = 
+            let x = FSharpCompletionProvider.ProvideCompletionsAsyncAux(checker, SourceText.From(fileContents), caretPosition, projectOptions, filePath, 0, (fun _ -> []), LanguageServicePerformanceOptions.Default, IntelliSenseOptions.Default) 
+                    |> Async.RunSynchronously 
+            x |> Option.defaultValue (ResizeArray())
+            |> Seq.toList
+            // sort items as Roslyn do - by `SortText`
+            |> List.sortBy (fun x -> x.SortText)
+
+        let actualNames = actual |> List.map (fun x -> x.DisplayText)
+
+        if actualNames <> expected then
+            Assert.Fail(sprintf "Expected:\n%s,\nbut was:\n%s\nactual with sort text:\n%s" 
+                                (String.Join("; ", expected |> List.map (sprintf "\"%s\""))) 
+                                (String.Join("; ", actualNames |> List.map (sprintf "\"%s\"")))
+                                (String.Join("\n", actual |> List.map (fun x -> sprintf "%s => %s" x.DisplayText x.SortText))))
+
+module FsxCompletionProviderTests =
+
+    let pathToThisDll = Assembly.GetExecutingAssembly().CodeBase
+
+    let getWorker () =
+
+        let adSetup =
+            let setup = new System.AppDomainSetup ()
+            setup.PrivateBinPath <- pathToThisDll
+            setup.ApplicationBase <- Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "SomeNonExistentDirectory")
+            setup
+
+        let ad = AppDomain.CreateDomain((Guid()).ToString(), null, adSetup)
+        (ad.CreateInstanceFromAndUnwrap(pathToThisDll, typeof<Worker>.FullName)) :?> Worker
+
+    [<Test>]
+    let fsiShouldTriggerCompletionInFsxFile() =
+    
+        let fileContents = """
+    fsi.
+    """
+        let expected = List<string>([
+            "CommandLineArgs"; "EventLoop"; "FloatingPointFormat"; "FormatProvider"; "PrintDepth"; 
+            "PrintLength"; "PrintSize"; "PrintWidth"; "ShowDeclarationValues"; "ShowIEnumerable"; 
+            "ShowProperties"; "AddPrinter"; "AddPrintTransformer"; "Equals"; "GetHashCode"; 
+            "GetType"; "ToString"; ])
+
+        // We execute in a seperate appdomain so that we can set BaseDirectory to a non-existent location
+        getWorker().VerifyCompletionListExactly(fileContents, "fsi.", expected)
+
+#if EXE
+ShouldTriggerCompletionInFsxFile()
+#endif
diff --git a/vsintegration/tests/UnitTests/VisualFSharp.UnitTests.fsproj b/vsintegration/tests/UnitTests/VisualFSharp.UnitTests.fsproj
index 6a3cae016a6..9598b23b5c2 100644
--- a/vsintegration/tests/UnitTests/VisualFSharp.UnitTests.fsproj
+++ b/vsintegration/tests/UnitTests/VisualFSharp.UnitTests.fsproj
@@ -148,6 +148,9 @@
     <Compile Include="CompletionProviderTests.fs">
       <Link>Roslyn\CompletionProviderTests.fs</Link>
     </Compile>
+    <Compile Include="FsxCompletionProviderTests.fs">
+      <Link>Roslyn\FsxCompletionProviderTests.fs</Link>
+    </Compile>
     <Compile Include="SignatureHelpProviderTests.fs">
       <Link>Roslyn\SignatureHelpProviderTests.fs</Link>
     </Compile>