diff --git a/src/server/project.ts b/src/server/project.ts
index 31546e2933..90d1e9c64e 100644
--- a/src/server/project.ts
+++ b/src/server/project.ts
@@ -312,7 +312,7 @@ namespace ts.server {
             // - newProgram is different from the old program and structure of the old program was not reused.
             if (!oldProgram || (this.program !== oldProgram && !oldProgram.structureIsReused)) {
                 hasChanges = true;
-                this.projectService.typingsCache.invalidateCachedTypingsForProject(this);
+                //this.projectService.typingsCache.invalidateCachedTypingsForProject(this);
                 if (oldProgram) {
                     for (const f of oldProgram.getSourceFiles()) {
                         if (this.program.getSourceFileByPath(f.path)) {
@@ -405,16 +405,25 @@ namespace ts.server {
 
                 const added: string[] = [];
                 const removed: string[] = [];
+                let invalidateTypings = false;
                 for (const id in currentFiles) {
                     if (hasProperty(currentFiles, id) && !hasProperty(lastReportedFileNames, id)) {
                         added.push(id);
+                        if (this.typingFiles.indexOf(id) < 0) {
+                            invalidateTypings = true;
+                            break;
+                        }
                     }
                 }
                 for (const id in lastReportedFileNames) {
                     if (hasProperty(lastReportedFileNames, id) && !hasProperty(currentFiles, id)) {
                         removed.push(id);
+                        invalidateTypings = true;
                     }
                 }
+                if (invalidateTypings) {
+                    this.projectService.typingsCache.invalidateCachedTypingsForProject(this);
+                }
                 this.lastReportedFileNames = currentFiles;
 
                 this.lastReportedFileNames = currentFiles;
diff --git a/src/server/typingsInstaller/nodeTypingsInstaller.ts b/src/server/typingsInstaller/nodeTypingsInstaller.ts
index 50a3626700..a5334c4d65 100644
--- a/src/server/typingsInstaller/nodeTypingsInstaller.ts
+++ b/src/server/typingsInstaller/nodeTypingsInstaller.ts
@@ -114,23 +114,29 @@ namespace ts.server.typingsInstaller {
         protected runInstall(cachePath: string, typingsToInstall: string[], postInstallAction: (installedTypings: string[]) => void): void {
             const id = this.installRunCount;
             this.installRunCount++;
-            const command = `npm install ${typingsToInstall.map(t => "@types/" + t).join(" ")} --save-dev`;
-            if (this.log.isEnabled()) {
-                this.log.writeLine(`Running npm install @types ${id}, command '${command}'. cache path '${cachePath}'`);
-            }
-            this.exec(command, { cwd: cachePath }, (err, stdout, stderr) => {
+            let installCount = 0;
+            const installedTypings: string[] = [];
+            const expr = /^.*(@types\/\w+)\S*\s*$/gm;
+            let match: RegExpExecArray;
+            for (const typing of typingsToInstall) {
+                const command = `npm install @types/${typing} --save-dev`;
                 if (this.log.isEnabled()) {
-                    this.log.writeLine(`npm install @types ${id} stdout: ${stdout}`);
-                    this.log.writeLine(`npm install @types ${id} stderr: ${stderr}`);
+                    this.log.writeLine(`Running npm install @types ${id}, command '${command}'. cache path '${cachePath}'`);
                 }
-                const installedTypings: string[] = [];
-                const expr = /^.*(node_modules)\\(@types)\\(\S+)\s*$/gm;
-                let match: RegExpExecArray;
-                while (match = expr.exec(stdout)) {
-                    installedTypings.push(`${match[1]}/${match[2]}/${match[3]}`);
-                }
-                postInstallAction(installedTypings);
-            });
+                this.exec(command, { cwd: cachePath }, (err, stdout, stderr) => {
+                    installCount++;
+                    if (this.log.isEnabled()) {
+                        this.log.writeLine(`npm install @types ${id} stdout: ${stdout}`);
+                        this.log.writeLine(`npm install @types ${id} stderr: ${stderr}`);
+                    }
+                    while (match = expr.exec(stdout)) {
+                        installedTypings.push(`node_modules/${match[1]}`);
+                    }
+                    if (installCount >= typingsToInstall.length) {
+                        postInstallAction(installedTypings);
+                    }
+                });
+            }
         }
     }