diff --git a/app.js b/app.js
index 170539a379ec55cdb371fac1076785c0afb04f0d..1fdccbbecfbfff2d19b0b5c59e379208ea52682f 100644
--- a/app.js
+++ b/app.js
@@ -9,8 +9,7 @@ const fsReaddir = require('fs-readdir');
 const JSZip = require('jszip');
 
 const exphbs = require('express-handlebars');
-// global.jQuery = require('jquery');
-// const bootstrap = require('bootstrap');
+
 //initializer
 const initGitRepos = require('./initializers/gitRepos.js');
 //load names of available download files
@@ -29,17 +28,16 @@ app.use(bodyParser.urlencoded({
 }));
 app.use(bodyParser.json());
 
-	//set handlebars as view engine
-	app.engine('.hbs', exphbs({extname: '.hbs'}));
-	app.set('view engine', '.hbs');
+//set handlebars as view engine
+app.engine('.hbs', exphbs({extname: '.hbs'}));
+app.set('view engine', '.hbs');
 
 	
 	//TODO add spinner for telling user to wait until initialization is done
 	
-	//initGitRepos.initialize(downloadFiles);
-
 	//routes
 	app.get('/', function(req, res){
+		//initGitRepos.initialize(downloadFiles);
 		res.render('home', {downloadFiles: downloadNames});
 	});
 
@@ -57,7 +55,7 @@ app.use(bodyParser.json());
 
 
 	app.get('/download', function(req, res, next){
-		//holds promises for backend and/or frontend
+		//holds promises for backend and/or frontend for synchronizing
 		const promiseArray = []
 		const checkedFiles = req.query.checkedFiles.split(',');
 
@@ -69,63 +67,63 @@ app.use(bodyParser.json());
 		frontendChecked = checkedFiles.find(function(file){
 			return file === 'explorviz-ui-frontend';
 		});
+//the user is not allowed to check plugins without having checked frontend or backend
+if(!(backendChecked || frontendChecked)){
+	res.render('home', {downloadFiles: downloadNames});
+}
 
-		if(!(backendChecked || frontendChecked)){
-			res.render('home', {downloadFiles: downloadNames});
-		}
-
-		if (backendChecked){
-
-			const fileName = backendChecked;
+if (backendChecked){
 
-			function backendAll(){
-				return backendFunctions.backendClean(fileName).then(function(){
-					return backendFunctions.backendPull(fileName).then(function(){
-						return backendFunctions.backendInstallAddons(checkedFiles,downloadFiles).then(function(){
-							return backendFunctions.backendBuild(fileName)
-						})
-					})
-				}).catch(function(error){
-					let response = 
-					'There was an error during your backend build. ' +
-					'Please contact "explorviz-developers-request@listserv.dfn.de" ' +
-					'and add the following information: ' + error;
-					res.send(response);
+	const fileName = backendChecked;
 
+	function backendAll(){
+		return backendFunctions.backendClean(fileName).then(function(){
+			return backendFunctions.backendPull(fileName).then(function(){
+				return backendFunctions.backendInstallAddons(checkedFiles,downloadFiles).then(function(){
+					return backendFunctions.backendBuild(fileName)
 				})
+			})
+		}).catch(function(error){
+			let response = 
+			'There was an error during your backend build. ' +
+			'Please contact "explorviz-developers-request@listserv.dfn.de" ' +
+			'and add the following information: ' + error;
+			res.send(response);
 
-			}
-			promiseArray.push(backendAll());
+		})
 
-		} 
+	}
+	promiseArray.push(backendAll());
 
-		
+} 
 
-		if (frontendChecked){
-			const fileName = frontendChecked;
-			const downloadURL = downloadFiles[frontendChecked]; 
 
-			function frontendAll() {
-				return frontendFunctions.frontendClean(fileName).then(function(){
-					return frontendFunctions.frontendPull(fileName).then(function(){
-						return frontendFunctions.frontendInstallAddons(fileName, checkedFiles, downloadFiles).then(function(){
-							return frontendFunctions.frontendBuild(fileName)
-						})
-					})
-				}).catch(function(error){
-					let response = 
-					'There was an error during your frontend build. ' +
-					'Please contact "explorviz-developers-request@listserv.dfn.de" ' +
-					'and add the following information: ' + error;
-					res.send(response);
 
+if (frontendChecked){
+	const fileName = frontendChecked;
+	const downloadURL = downloadFiles[frontendChecked]; 
+
+	function frontendAll() {
+		return frontendFunctions.frontendClean(fileName).then(function(){
+			return frontendFunctions.frontendPull(fileName).then(function(){
+				return frontendFunctions.frontendInstallAddons(fileName, checkedFiles, downloadFiles).then(function(){
+					return frontendFunctions.frontendBuild(fileName)
 				})
-			}
-			promiseArray.push(frontendAll());
+			})
+		}).catch(function(error){
+			let response = 
+			'There was an error during your frontend build. ' +
+			'Please contact "explorviz-developers-request@listserv.dfn.de" ' +
+			'and add the following information: ' + error;
+			res.send(response);
+
+		})
+	}
+	promiseArray.push(frontendAll());
 
-		};
+};
 
-		finalizeZip();
+finalizeZip();
 
 
 function finalizeZip(){
@@ -146,8 +144,15 @@ function createZip(zip){
 			console.log('error in createZip:', error);
 		}).on('finish', function () {
 			console.log('explorviz-builds.zip written.');
-			res.download('explorviz-builds.zip');
-			//how to redirect to home page?
+			res.download('explorviz-builds.zip', function(error){
+				if(error){
+					let response = 
+					'There was an error during your build. ' +
+					'Please contact "explorviz-developers-request@listserv.dfn.de" ' +
+					'and add the following information: ' + error;
+					res.send(response);
+				} 
+			});
 		}); 
 
 	})
@@ -159,5 +164,6 @@ function createZip(zip){
 });
 
 
-app.listen(3000);
-console.log("Downloader started on port 3000.");
\ No newline at end of file
+
+	app.listen(3000);
+	console.log("Downloader started on port 3000.");
\ No newline at end of file
diff --git a/initializers/gitRepos.js b/initializers/gitRepos.js
index d69b7cd8139064b97bd0d2f1b8cf07ff31cb968b..cc0f89b76306df5d353e457450b79f96b8eb52bb 100644
--- a/initializers/gitRepos.js
+++ b/initializers/gitRepos.js
@@ -89,12 +89,6 @@ var exec       = require('child_process').exec;
 
 };
 
-
-// module.exports = {
-//   initBackend,
-//   initBackendPlugins,
-//   initFrontend
-// }
 module.exports = {
   initialize
 }
\ No newline at end of file
diff --git a/package.json b/package.json
index 1ae2bde79eaa7083fe2c1a60a27cd49f12126ced..ec98e9a223a817e51515451f06d597de267eb080 100644
--- a/package.json
+++ b/package.json
@@ -10,15 +10,12 @@
   "license": "Apache-2.0",
   "dependencies": {
     "body-parser": "^1.17.1",
-    "bootstrap": "^3.3.7",
     "child_process": "^1.0.2",
     "express": "^4.15.2",
     "express-handlebars": "^3.0.0",
     "fs": "0.0.1-security",
     "fs-readdir": "0.0.3",
-    "jquery": "^3.2.1",
     "jszip": "^3.1.3",
-    "node-zip": "^1.1.1",
     "path": "^0.12.7",
     "spinkit": "^1.2.5"
   },