diff --git a/.travis.yml b/.travis.yml
index 42b86fb0706..8b924a336fe 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -27,7 +27,7 @@ install:
   - if [ "$TRAVIS_NODE_VERSION" = "6" ]; then
       npm uninstall typemock @typescript/vfs @typescript/vfs-path @typescript/vfs-core @typescript/vfs-errors --no-save;
       npm run build:private-packages;
-      npm install file:scripts/typemock file:scripts/vfs file:scripts/vfs-path --no-save;
+      npm install file:scripts/typemock file:scripts/vfs-errors file:scripts/vfs-core file:scripts/vfs-path file:scripts/vfs --no-save;
     fi
 
 cache:
diff --git a/Jakefile.js b/Jakefile.js
index a1b847d0511..c7f69bed8fa 100644
--- a/Jakefile.js
+++ b/Jakefile.js
@@ -228,17 +228,7 @@ var compilerFilename = "tsc.js";
 var LKGCompiler = path.join(LKGDirectory, compilerFilename);
 var builtLocalCompiler = path.join(builtLocalDirectory, compilerFilename);
 
-/**
- * Executes the compiler
- * @param {boolean} useBuiltCompiler 
- * @param {string[]} args 
- * @param {function([Error]): void} [callback] A callback to execute after the compilation process ends.
- */
-function execCompiler(useBuiltCompiler, args, callback) {
-    var compilerPath = useBuiltCompiler ? builtLocalCompiler : LKGCompiler;
-    var cmd = host + " " + compilerPath + " " + args.join(" ");
-    console.log(cmd + "\n");
-
+function execAsync(cmd, callback) {
     var ex = jake.createExec([cmd]);
     // Add listeners for output and error
     ex.addListener("stdout", function (output) {
@@ -254,12 +244,31 @@ function execCompiler(useBuiltCompiler, args, callback) {
     });
     ex.addListener("error", function (error) {
         if (callback) {
-            callback(error || new Error("Compilation unsuccessful"));
+            callback(error || new Error());
         }
     });
     ex.run();
 }
 
+function execNpmInstall(packages, callback) {
+    var cmd = "npm install --no-save " + packages.join(" ");
+    console.log(cmd);
+    execAsync(cmd, callback);
+}
+
+/**
+ * Executes the compiler
+ * @param {boolean} useBuiltCompiler
+ * @param {string[]} args
+ * @param {function([Error]): void} [callback] A callback to execute after the compilation process ends.
+ */
+function execCompiler(useBuiltCompiler, args, callback) {
+    var compilerPath = useBuiltCompiler ? builtLocalCompiler : LKGCompiler;
+    var cmd = host + " " + compilerPath + " " + args.join(" ");
+    console.log(cmd + "\n");
+    execAsync(cmd, callback);
+}
+
 /** Compiles a file from a list of sources
  * @param {string} outFile value for '--out' command line option
  * @param {string[]} sources an array of the names of the source files
@@ -287,10 +296,10 @@ function compile(outFile, sources, prefixes, useBuiltCompiler, opts, callback) {
     var startCompileTime = mark();
     opts = opts || {};
     var options = [
-        "--noImplicitAny", 
-        "--noImplicitThis", 
-        "--alwaysStrict", 
-        "--noEmitOnError", 
+        "--noImplicitAny",
+        "--noImplicitThis",
+        "--alwaysStrict",
+        "--noEmitOnError",
         "--pretty",
         "--newLine LF"
     ];
@@ -378,18 +387,18 @@ function compile(outFile, sources, prefixes, useBuiltCompiler, opts, callback) {
                     prependFile(prefixes[i], outFile);
                 }
             }
-    
+
             if (callback) {
                 callback();
             }
-    
+
             complete();
         }
         measure(startCompileTime);
     });
 }
 
-/** 
+/**
  * Compiles a file from a list of sources
  * @param {string} outFile the target file name
  * @param {string[]} sources an array of the names of the source files
@@ -834,29 +843,53 @@ task("vfs-errors", function () {
 }, { async: true });
 
 task("vfs-path", ["vfs-core", "vfs-errors"], function () {
-    var startCompileTime = mark();
-    execCompiler(/*useBuiltCompiler*/ false, ["-p", "scripts/vfs-path/tsconfig.json"], function (error) {
-        if (error) {
-            fail("Compilation unsuccessful.");
-        }
-        else {
-            complete();
-        }
-        measure(startCompileTime);
-    });
+    if (process.env.INSTALL_PRIVATE_DEPS) {
+        execNpmInstall(["file:scripts/vfs-core", "file:scripts/vfs-errors"], function (error) {
+            if (error) return fail(error);
+            compile();
+        });
+    }
+    else {
+        compile();
+    }
+
+    function compile() {
+        var startCompileTime = mark();
+        execCompiler(/*useBuiltCompiler*/ false, ["-p", "scripts/vfs-path/tsconfig.json"], function (error) {
+            if (error) {
+                fail("Compilation unsuccessful.");
+            }
+            else {
+                complete();
+            }
+            measure(startCompileTime);
+        });
+    }
 }, { async: true });
 
-task("vfs", ["vfs-path", "vfs-core", "vfs-errors"], function () {
-    var startCompileTime = mark();
-    execCompiler(/*useBuiltCompiler*/ false, ["-p", "scripts/vfs/tsconfig.json"], function (error) {
-        if (error) {
-            fail("Compilation unsuccessful.");
-        }
-        else {
-            complete();
-        }
-        measure(startCompileTime);
-    });
+task("vfs", ["vfs-core", "vfs-errors", "vfs-path", "typemock"], function () {
+    if (process.env.INSTALL_PRIVATE_DEPS) {
+        execNpmInstall(["file:scripts/vfs-path", "file:scripts/typemock"], function (error) {
+            if (error) return fail(error);
+            compile();
+        });
+    }
+    else {
+        compile();
+    }
+
+    function compile() {
+        var startCompileTime = mark();
+        execCompiler(/*useBuiltCompiler*/ false, ["-p", "scripts/vfs/tsconfig.json"], function (error) {
+            if (error) {
+                fail("Compilation unsuccessful.");
+            }
+            else {
+                complete();
+            }
+            measure(startCompileTime);
+        });
+    }
 }, { async: true });
 
 task("private-packages", ["typemock", "vfs"]);
@@ -866,7 +899,7 @@ var run = path.join(builtLocalDirectory, "run.js");
 compileFile(
     /*outFile*/ run,
     /*source*/ harnessSources,
-    /*prereqs*/[builtLocalDirectory, tscFile, tsserverLibraryFile, "typemock"].concat(libraryTargets).concat(servicesSources).concat(harnessSources),
+    /*prereqs*/[builtLocalDirectory, tscFile, tsserverLibraryFile, "private-packages"].concat(libraryTargets).concat(servicesSources).concat(harnessSources),
     /*prefixes*/[],
     /*useBuiltCompiler:*/ true,
     /*opts*/ { types: ["node", "mocha", "chai"], lib: "es6" });
diff --git a/jenkins.sh b/jenkins.sh
index ef9f9535c6f..fe1a88fbbe0 100755
--- a/jenkins.sh
+++ b/jenkins.sh
@@ -14,7 +14,7 @@ npm install
 if [ "$1" = "6" ]; then
     npm uninstall typemock @typescript/vfs @typescript/vfs-path @typescript/vfs-core @typescript/vfs-errors --no-save;
     npm run build:private-packages;
-    npm install file:scripts/typemock file:scripts/vfs file:scripts/vfs-path --no-save;
+    npm install file:scripts/typemock file:scripts/vfs-errors file:scripts/vfs-core file:scripts/vfs-path file:scripts/vfs --no-save;
 fi
 
 npm update
diff --git a/package.json b/package.json
index 66af769602d..f6c9cac9792 100644
--- a/package.json
+++ b/package.json
@@ -93,7 +93,7 @@
         "build": "npm run build:compiler && npm run build:tests",
         "build:compiler": "jake local",
         "build:tests": "jake tests",
-        "build:private-packages": "jake private-packages",
+        "build:private-packages": "jake private-packages INSTALL_PRIVATE_DEPS=1",
         "start": "node lib/tsc",
         "clean": "jake clean",
         "gulp": "gulp",
diff --git a/src/harness/compiler.ts b/src/harness/compiler.ts
index 00647dccf20..b6481612d80 100644
--- a/src/harness/compiler.ts
+++ b/src/harness/compiler.ts
@@ -234,7 +234,7 @@ namespace compiler {
         }
         else {
             [project] = host.vfs.scanSync(".", "ancestors-or-self", {
-                accept: (path: string, stats: vfs.FileSystem) => stats.isFile() && host.vfs.stringComparer(vpath.basename(path), "tsconfig.json") === 0
+                accept: (path, stats) => stats.isFile() && host.vfs.stringComparer(vpath.basename(path), "tsconfig.json") === 0
             });
         }
 
diff --git a/src/harness/harnessLanguageService.ts b/src/harness/harnessLanguageService.ts
index af14f2c2f8f..7ad66449efe 100644
--- a/src/harness/harnessLanguageService.ts
+++ b/src/harness/harnessLanguageService.ts
@@ -131,7 +131,7 @@ namespace Harness.LanguageService {
         public getFilenames(): string[] {
             const fileNames: string[] = [];
             this.vfs.scanSync("/", "descendants-or-self", {
-                accept: (path: string, stats: vfs.FileSystem) => {
+                accept: (path, stats) => {
                     if (stats.isFile()) {
                         const scriptInfo = this.vfs.filemeta(path).get("scriptInfo") as ScriptInfo;
                         if (scriptInfo && scriptInfo.isRootFile) {