diff --git a/lib/uploadhandler.js b/lib/uploadhandler.js
index ece4b55..8403595 100644
--- a/lib/uploadhandler.js
+++ b/lib/uploadhandler.js
@@ -4,7 +4,8 @@ var EventEmitter = require('events').EventEmitter,
     formidable = require('formidable'),
     imageMagick = require('imagemagick'),
     mkdirp = require('mkdirp'),
-    _ = require('lodash');
+    _ = require('lodash'),
+    async = require('async');
 
 module.exports = function (options) {
 
@@ -34,19 +35,24 @@ module.exports = function (options) {
         this.noCache();
         var files = [];
         fs.readdir(options.uploadDir(), _.bind(function (err, list) {
-            _.each(list, function (name) {
-                var stats = fs.statSync(options.uploadDir() + '/' + name),
-                    fileInfo;
-                if (stats.isFile()) {
-                    fileInfo = new FileInfo({
-                        name: name,
-                        size: stats.size
-                    });
-                    this.initUrls(fileInfo);
-                    files.push(fileInfo);
-                }
-            }, this);
-            this.callback({files: files});
+            async.each(list, _.bind(function(name, cb) {
+                fs.stat(options.uploadDir() + '/' + name, _.bind(function(err, stats) {
+                    if (!err && stats.isFile()) {
+                        var fileInfo = new FileInfo({
+                            name: name,
+                            size: stats.size
+                        });
+                        this.initUrls(fileInfo, function(err) {
+                            files.push(fileInfo);
+                            cb(err);
+                        });
+                    }
+                    else cb(err);
+                }, this));
+            }, this),
+            _.bind(function(err) {
+                this.callback({files: files});
+            }, this));
         }, this));
     };
 
@@ -60,11 +66,15 @@ module.exports = function (options) {
             redirect,
             finish = _.bind(function () {
                 if (!--counter) {
-                    _.each(files, function (fileInfo) {
-                        this.initUrls(fileInfo);
-                        this.emit('end', fileInfo);
-                    }, this);
-                    this.callback({files: files}, redirect);
+                    async.each(files, _.bind(function(fileInfo, cb) {
+                        this.initUrls(fileInfo, _.bind(function(err) {
+                            this.emit('end', fileInfo);
+                            cb(err);
+                        }, this));
+                    }, this),
+                    _.bind(function(err) {
+                        this.callback({files: files}, redirect);
+                    }, this));
                 }
             }, this);
 
@@ -86,56 +96,58 @@ module.exports = function (options) {
                 }
             })
             .on('file', function (name, file) {
+                counter++;
                 var fileInfo = map[path.basename(file.path)];
-                if (fs.existsSync(file.path)) {
-                    fileInfo.size = file.size;
-                    if (!fileInfo.validate()) {
-                        fs.unlink(file.path);
-                        return;
-                    }
-
-                    var generatePreviews = function () {
-                        if (options.imageTypes.test(fileInfo.name)) {
-                            _.each(options.imageVersions, function (value, version) {
-                                // creating directory recursive
-                                if (!fs.existsSync(options.uploadDir() + '/' + version + '/'))
-                                    mkdirp.sync(options.uploadDir() + '/' + version + '/');
-
-                                counter++;
-                                var opts = options.imageVersions[version];
-                                imageMagick.resize({
-                                    width: opts.width,
-                                    height: opts.height,
-                                    srcPath: options.uploadDir() + '/' + fileInfo.name,
-                                    dstPath: options.uploadDir() + '/' + version + '/' + fileInfo.name,
-                                    customArgs: opts.imageArgs || ['-auto-orient']
-                                }, finish);
-                            });
+                fs.exists(file.path, function(exists) {
+                    if (exists) {
+                        fileInfo.size = file.size;
+                        if (!fileInfo.validate()) {
+                            fs.unlink(file.path);
+                            finish();
+                            return;
                         }
-                    }
 
-                    if (!fs.existsSync(options.uploadDir() + '/'))
-                        mkdirp.sync(options.uploadDir() + '/');
+                        var generatePreviews = function () {
+                            if (options.imageTypes.test(fileInfo.name)) {
+                                _.each(options.imageVersions, function (value, version) {
+                                    counter++;
+                                    // creating directory recursive
+                                    mkdirp(options.uploadDir() + '/' + version + '/', function (err, made) {
+                                        var opts = options.imageVersions[version];
+                                        imageMagick.resize({
+                                            width: opts.width,
+                                            height: opts.height,
+                                            srcPath: options.uploadDir() + '/' + fileInfo.name,
+                                            dstPath: options.uploadDir() + '/' + version + '/' + fileInfo.name,
+                                            customArgs: opts.imageArgs || ['-auto-orient']
+                                        }, finish);
+                                    });
+                                });
+                            }
+                        }
 
-                    counter++;
-                    fs.rename(file.path, options.uploadDir() + '/' + fileInfo.name, function (err) {
-                        if (!err) {
-                            generatePreviews();
-                            finish();
-                        } else {
-                            var is = fs.createReadStream(file.path);
-                            var os = fs.createWriteStream(options.uploadDir() + '/' + fileInfo.name);
-                            is.on('end', function (err) {
+                        mkdirp(options.uploadDir() + '/', function(err, made) {
+                            fs.rename(file.path, options.uploadDir() + '/' + fileInfo.name, function (err) {
                                 if (!err) {
-                                    fs.unlinkSync(file.path);
                                     generatePreviews();
+                                    finish();
+                                } else {
+                                    var is = fs.createReadStream(file.path);
+                                    var os = fs.createWriteStream(options.uploadDir() + '/' + fileInfo.name);
+                                    is.on('end', function (err) {
+                                        if (!err) {
+                                            fs.unlink(file.path);
+                                            generatePreviews();
+                                        }
+                                        finish();
+                                    });
+                                    is.pipe(os);
                                 }
-                                finish();
                             });
-                            is.pipe(os);
-                        }
-                    });
-                }
+                        });
+                    }
+                    else finish();
+                });
             })
             .on('aborted', function () {
                 _.each(tmpFiles, function (file) {
@@ -168,15 +180,17 @@ module.exports = function (options) {
         });
     };
 
-    UploadHandler.prototype.initUrls = function (fileInfo) {
+    UploadHandler.prototype.initUrls = function (fileInfo, cb) {
         var baseUrl = (options.ssl ? 'https:' : 'http:') + '//' + (options.hostname || this.req.get('Host'));
         fileInfo.setUrl(null, baseUrl + options.uploadUrl());
         fileInfo.setUrl('delete', baseUrl + this.req.originalUrl);
-        _.each(options.imageVersions, function (value, version) {
-            if (fs.existsSync(options.uploadDir() + '/' + version + '/' + fileInfo.name)) {
-                fileInfo.setUrl(version, baseUrl + options.uploadUrl() + '/' + version);
-            }
-        }, this);
+        async.each(Object.keys(options.imageVersions), function(version, cb) {
+            fs.exists(options.uploadDir() + '/' + version + '/' + fileInfo.name, function(exists) {
+                if (exists) fileInfo.setUrl(version, baseUrl + options.uploadUrl() + '/' + version);
+                cb(null);
+            })
+        },
+        cb);
     };
 
     return UploadHandler;
diff --git a/package.json b/package.json
index ea657a4..eaaa4f5 100644
--- a/package.json
+++ b/package.json
@@ -13,7 +13,8 @@
     "formidable": ">=1.0.11",
     "imagemagick": ">=0.1.2",
     "lodash": ">= 0.9.2",
-    "mkdirp": ">= 0.3.4"
+    "mkdirp": ">= 0.3.4",
+    "async": "*"
   },
   "engines": {
     "node": ">= 0.8.8"