diff --git a/kcc/KCC_gui.py b/kcc/KCC_gui.py
index 974976b..344c194 100644
--- a/kcc/KCC_gui.py
+++ b/kcc/KCC_gui.py
@@ -109,6 +109,9 @@ class WebServerHandler(BaseHTTPRequestHandler):
             if self.path.endswith('.mobi'):
                 mimetype = 'application/x-mobipocket-ebook'
                 sendReply = True
+            if self.path.endswith('.azw3'):
+                mimetype = 'application/x-mobipocket-ebook'
+                sendReply = True
             if self.path.endswith('.epub'):
                 mimetype = 'application/epub+zip'
                 sendReply = True
@@ -491,10 +494,11 @@ class WorkerThread(QtCore.QThread):
                                 GUI.progress.content = ''
                                 mobiPath = item.replace('.epub', '.mobi')
                                 os.remove(mobiPath + '_toclean')
-                                GUI.completedWork[os.path.basename(mobiPath).encode('utf-8')] = \
-                                    mobiPath.encode('utf-8')
-                                self.emit(QtCore.SIGNAL("addMessage"), 'Cleaning MOBI files... <b>Done!</b>', 'info',
-                                          True)
+                                if profile in ['K345', 'KHD', 'KF', 'KFHD', 'KFHD8', 'KFHDX', 'KFHDX8', 'KFA']:
+                                    move(mobiPath, mobiPath.replace('.mobi', '.azw3'))
+                                    mobiPath = item.replace('.mobi', '.azw3')
+                                GUI.completedWork[os.path.basename(mobiPath).encode('utf-8')] = mobiPath.encode('utf-8')
+                                self.emit(QtCore.SIGNAL("addMessage"), 'Cleaning MOBI files... <b>Done!</b>', 'info', True)
                         else:
                             GUI.progress.content = ''
                             for item in outputPath: