diff --git a/itchat/components/login.py b/itchat/components/login.py
index 3bba665c..c35d1ecd 100644
--- a/itchat/components/login.py
+++ b/itchat/components/login.py
@@ -27,12 +27,15 @@ def load_login(core):
 
 def login(self, enableCmdQR=False, picDir=None, qrCallback=None,
         loginCallback=None, exitCallback=None):
-    if self.alive:
+    if self.alive or self.isLogging:
         logger.warning('itchat has already logged in.')
         return
-    while 1:
+    self.isLogging = True
+    while self.isLogging:
         uuid = push_login(self)
-        if not uuid:
+        if uuid:
+            qrStorage = io.BytesIO()
+        else:
             logger.info('Getting uuid of QR code.')
             while not self.get_QRuuid():
                 time.sleep(1)
@@ -56,6 +59,8 @@ def login(self, enableCmdQR=False, picDir=None, qrCallback=None,
         if isLoggedIn:
             break
         logger.info('Log in time out, reloading QR code.')
+    else:
+        return # log in process is stopped by user
     logger.info('Loading the contact, this may take a little while.')
     self.web_init()
     self.show_mobile_login()
@@ -68,6 +73,7 @@ def login(self, enableCmdQR=False, picDir=None, qrCallback=None,
             os.remove(picDir or config.DEFAULT_QR)
         logger.info('Login successfully as %s' % self.storageClass.nickName)
     self.start_receiving(exitCallback)
+    self.isLogging = False
 
 def push_login(core):
     cookiesDict = core.s.cookies.get_dict()
@@ -311,6 +317,7 @@ def logout(self):
         headers = { 'User-Agent' : config.USER_AGENT }
         self.s.get(url, params=params, headers=headers)
         self.alive = False
+    self.isLogging = False
     self.s.cookies.clear()
     del self.chatroomList[:]
     del self.memberList[:]
diff --git a/itchat/components/messages.py b/itchat/components/messages.py
index 5c685140..3f5652bc 100644
--- a/itchat/components/messages.py
+++ b/itchat/components/messages.py
@@ -256,7 +256,7 @@ def upload_file(self, fileDir, isPicture=False, isVideo=False,
     fileSize = os.path.getsize(fileDir)
     fileSymbol = 'pic' if isPicture else 'video' if isVideo else'doc'
     with open(fileDir, 'rb') as f: fileMd5 = hashlib.md5(f.read()).hexdigest()
-    file = open(fileDir, 'rb')
+    file_ = open(fileDir, 'rb')
     chunks = int((fileSize - 1) / 524288) + 1
     clientMediaId = int(time.time() * 1e4)
     uploadMediaRequest = json.dumps(OrderedDict([
@@ -271,10 +271,13 @@ def upload_file(self, fileDir, isPicture=False, isVideo=False,
         ('ToUserName', toUserName),
         ('FileMd5', fileMd5)]
         ), separators = (',', ':'))
+    r = {'BaseResponse': {'Ret': -1005, 'ErrMsg': 'Empty file detected'}}
     for chunk in range(chunks):
         r = upload_chunk_file(self, fileDir, fileSymbol, fileSize,
-            file, chunk, chunks, uploadMediaRequest)
-    file.close()
+            file_, chunk, chunks, uploadMediaRequest)
+    file_.close()
+    if isinstance(r, dict):
+        return ReturnValue(r)
     return ReturnValue(rawResponse=r)
 
 def upload_chunk_file(core, fileDir, fileSymbol, fileSize,
diff --git a/itchat/config.py b/itchat/config.py
index 41c7e7df..acbe2f53 100644
--- a/itchat/config.py
+++ b/itchat/config.py
@@ -1,6 +1,6 @@
 import os, platform
 
-VERSION = '1.2.28'
+VERSION = '1.2.29'
 BASE_URL = 'https://login.weixin.qq.com'
 OS = platform.system() #Windows, Linux, Darwin
 DIR = os.getcwd()
diff --git a/itchat/core.py b/itchat/core.py
index 9866fc4d..dea80903 100644
--- a/itchat/core.py
+++ b/itchat/core.py
@@ -17,7 +17,7 @@ def __init__(self):
                 - it's 5 now, but actually even 1 is enough
                 - failing is failing
         '''
-        self.alive = False
+        self.alive, self.isLogging = False, False
         self.storageClass = storage.Storage()
         self.memberList = self.storageClass.memberList
         self.mpList = self.storageClass.mpList