diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index 8b38d56c2b2..99ca9377d54 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1219,7 +1219,7 @@ namespace ts {
                 (oldOptions.noLib !== options.noLib) ||
                 (oldOptions.jsx !== options.jsx) ||
                 (oldOptions.allowJs !== options.allowJs) ||
-		(oldOptions.disableSizeLimit !== options.disableSizeLimit) ||
+                (oldOptions.disableSizeLimit !== options.disableSizeLimit) ||
                 (oldOptions.rootDir !== options.rootDir) ||
                 (oldOptions.typesSearchPaths !== options.typesSearchPaths) ||
                 (oldOptions.configFilePath !== options.configFilePath) ||
diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
index 1e04e97e4c5..659c021c6be 100644
--- a/src/compiler/sys.ts
+++ b/src/compiler/sys.ts
@@ -28,7 +28,7 @@ namespace ts {
         getDirectories(path: string): string[];
         readDirectory(path: string, extension?: string, exclude?: string[]): string[];
         readDirectoryWithMultipleExtensions?(path: string, extensions: string[], exclude?: string[]): string[];
-	getModifiedTime?(path: string): Date;
+        getModifiedTime?(path: string): Date;
         createHash?(data: string): string;
         getMemoryUsage?(): number;
         exit(exitCode?: number): void;
@@ -549,7 +549,7 @@ namespace ts {
                 getDirectories,
                 readDirectory,
                 readDirectoryWithMultipleExtensions,
-		getModifiedTime(path) {
+                getModifiedTime(path) {
                     try {
                         return _fs.statSync(path).mtime;
                     }
diff --git a/src/server/editorServices.ts b/src/server/editorServices.ts
index 9f361cb3703..bd29dc65ac4 100644
--- a/src/server/editorServices.ts
+++ b/src/server/editorServices.ts
@@ -1217,7 +1217,7 @@ namespace ts.server {
             else {
                 this.log("No config files found.");
             }
-	    this.log("end openOrUpdateConfiguredProjectForFile: " + new Date().getTime());
+            this.log("end openOrUpdateConfiguredProjectForFile: " + new Date().getTime());
             return configFileName ? { configFileName } : {};
         }
 
@@ -1398,7 +1398,7 @@ namespace ts.server {
             }
         }
 
-        updateConfiguredProject(project: Project) {
+        updateConfiguredProject(project: Project): Diagnostic[] {
             if (!this.host.fileExists(project.projectFilename)) {
                 this.log("Config file deleted");
                 this.removeProject(project);
@@ -1434,9 +1434,6 @@ namespace ts.server {
                                 const info = this.openFile(rootFilename, /*openedByClient*/ false);
                                 project.addRoot(info);
                             }
-                            else {
-                                return { errorMsg: "specified file " + rootFilename + " not found" };
-                            }
                         }
                         project.finishGraph();
                         return;
@@ -1460,9 +1457,6 @@ namespace ts.server {
                     for (const fileName of fileNamesToAdd) {
                         let info = this.getScriptInfo(fileName);
                         if (!info) {
-                            if (!this.host.fileExists(info.fileName)) {
-                                return { errorMsg: "specified file " + info.fileName + " not found" };
-                            }
                             info = this.openFile(fileName, /*openedByClient*/ false);
                         }
                         else {
diff --git a/src/server/session.ts b/src/server/session.ts
index 6f07e979906..17fe4b758f2 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -444,11 +444,12 @@ namespace ts.server {
             const file = ts.normalizePath(fileName);
             const info = this.projectService.getScriptInfo(file);
             const projects = this.projectService.findReferencingProjects(info);
-            if (!projects.length) {
+            const projectsWithLanguageServiceEnabeld = ts.filter(projects, p => !p.languageServiceDiabled);
+            if (projects.length === 0 || projectsWithLanguageServiceEnabeld.length === 0) {
                 throw Errors.NoProject;
             }
 
-            const defaultProject = projects[0];
+            const defaultProject = projectsWithLanguageServiceEnabeld[0];
             // The rename info should be the same for every project
             const defaultProjectCompilerService = defaultProject.compilerService;
             const position = defaultProjectCompilerService.host.lineOffsetToPosition(file, line, offset);
@@ -465,7 +466,7 @@ namespace ts.server {
             }
 
             const fileSpans = combineProjectOutput(
-                projects,
+                projectsWithLanguageServiceEnabeld,
                 (project: Project) => {
                     const compilerService = project.compilerService;
                     const renameLocations = compilerService.languageService.findRenameLocations(file, position, findInStrings, findInComments);
@@ -526,11 +527,12 @@ namespace ts.server {
             const file = ts.normalizePath(fileName);
             const info = this.projectService.getScriptInfo(file);
             const projects = this.projectService.findReferencingProjects(info);
-            if (!projects.length) {
+            const projectsWithLanguageServiceEnabeld = ts.filter(projects, p => !p.languageServiceDiabled);
+            if (projects.length === 0 || projectsWithLanguageServiceEnabeld.length === 0) {
                 throw Errors.NoProject;
             }
 
-            const defaultProject = projects[0];
+            const defaultProject = projectsWithLanguageServiceEnabeld[0];
             const position = defaultProject.compilerService.host.lineOffsetToPosition(file, line, offset);
             const nameInfo = defaultProject.compilerService.languageService.getQuickInfoAtPosition(file, position);
             if (!nameInfo) {
@@ -542,7 +544,7 @@ namespace ts.server {
             const nameColStart = defaultProject.compilerService.host.positionToLineOffset(file, nameSpan.start).offset;
             const nameText = defaultProject.compilerService.host.getScriptSnapshot(file).getText(nameSpan.start, ts.textSpanEnd(nameSpan));
             const refs = combineProjectOutput<protocol.ReferencesResponseItem>(
-                projects,
+                projectsWithLanguageServiceEnabeld,
                 (project: Project) => {
                     const compilerService = project.compilerService;
                     const references = compilerService.languageService.getReferencesAtPosition(file, position);
@@ -902,13 +904,13 @@ namespace ts.server {
             const file = ts.normalizePath(fileName);
             const info = this.projectService.getScriptInfo(file);
             const projects = this.projectService.findReferencingProjects(info);
-            const defaultProject = projects[0];
-            if (!defaultProject) {
+            const projectsWithLanguageServiceEnabeld = ts.filter(projects, p => !p.languageServiceDiabled);
+            if (projects.length === 0 || projectsWithLanguageServiceEnabeld.length === 0) {
                 throw Errors.NoProject;
             }
 
             const allNavToItems = combineProjectOutput(
-                projects,
+                projectsWithLanguageServiceEnabeld,
                 (project: Project) => {
                     const compilerService = project.compilerService;
                     const navItems = compilerService.languageService.getNavigateToItems(searchValue, maxResultCount);