diff --git a/oml/item/api.py b/oml/item/api.py
index b614a1f..230be98 100644
--- a/oml/item/api.py
+++ b/oml/item/api.py
@@ -328,6 +328,8 @@ def _import(data):
             mode copy|move
         }
     '''
+    if 'cancel' in state.activity:
+        del state.activity['cancel']
     state.tasks.queue('import', data)
     return {}
 actions.register(_import, 'import', cache=False)
diff --git a/oml/item/models.py b/oml/item/models.py
index daad15c..3c7ec22 100644
--- a/oml/item/models.py
+++ b/oml/item/models.py
@@ -371,9 +371,11 @@ class Item(db.Model):
                         break
 
     def update_cover(self):
+        logger.debug('update cover %s', self.id)
         key = 'cover:%s'%self.id
         cover = None
         if 'cover' in self.meta and self.meta['cover']:
+            logger.debug('download cover %s %s', self.id, self.meta['cover'])
             try:
                 cover = ox.cache.read_url(self.meta['cover'])
             except:
@@ -389,7 +391,9 @@ class Item(db.Model):
                 self.info['coverRatio'] = self.info['previewRatio']
             elif 'coverRatio' in self.info:
                 del self.info['coverRatio']
+        logger.debug('clear cover:%s:', self.id)
         icons.clear('cover:%s:' % self.id)
+        logger.debug('update_cover done')
 
     def get_preview(self):
         key = 'preview:%s'%self.id
@@ -400,6 +404,7 @@ class Item(db.Model):
                 icons[key] = preview
 
     def update_preview(self):
+        logger.debug('update_preview %s', self.id)
         key = 'preview:%s'%self.id
         preview = self.extract_preview()
         if preview:
@@ -416,7 +421,9 @@ class Item(db.Model):
                 self.info['previewRatio'] = self.info['coverRatio']
             elif 'previewRatio' in self.info:
                 del self.info['previewRatio']
+        logger.debug('clear preview:%s:', self.id)
         icons.clear('preview:%s:' % self.id)
+        logger.debug('update_preview done %s', self.id)
 
     def update_icons(self):
         self.update_cover()
@@ -438,7 +445,8 @@ class Item(db.Model):
             if 'isbn' in self.meta:
                 data = meta.lookup('isbn', self.meta['isbn'])
                 if data:
-                    self.meta.update(data)
+                    for key in data:
+                        self.meta[key] = data[key]
 
     def queue_download(self):
         u = state.user()
diff --git a/oml/item/scan.py b/oml/item/scan.py
index d7de090..59ccb75 100644
--- a/oml/item/scan.py
+++ b/oml/item/scan.py
@@ -52,17 +52,23 @@ def remove_missing():
 def add_file(id, f, prefix, from_=None):
     user = state.user()
     path = f[len(prefix):]
+    logger.debug('extract metadata %s %s', id, path)
     data = media.metadata(f, from_)
+    logger.debug('create file %s %s', id, path)
     file = File.get_or_create(id, data, path)
     item = file.item
     item.add_user(user)
     item.added = datetime.utcnow()
+    logger.debug('load metadata %s %s', id, path)
     item.load_metadata()
     Changelog.record(user, 'additem', item.id, file.info)
     Changelog.record(user, 'edititem', item.id, item.meta)
+    logger.debug('extract icons %s %s', id, path)
     item.update_icons()
     item.modified = datetime.utcnow()
+    logger.debug('save item %s', id)
     item.update()
+    logger.debug('added file %s', id)
     return file
 
 def run_scan():
@@ -103,8 +109,12 @@ def run_scan():
 
 def run_import(options=None):
     options = options or {}
-
     logger.debug('run_import')
+    if state.activity.get('cancel'):
+        logger.debug('import canceled')
+        state.activity = {}
+        return
+    state.activity = {}
     prefs = settings.preferences
     prefix = os.path.expanduser(options.get('path', prefs['importPath']))
     if os.path.islink(prefix):
@@ -148,6 +158,7 @@ def run_import(options=None):
                 books.append(f)
                 count += 1
                 if state.activity.get('cancel'):
+                    logger.debug('active import canceled')
                     state.activity = {}
                     return
                 if count % 1000 == 0:
diff --git a/oml/tasks.py b/oml/tasks.py
index 430ea19..ca84b60 100644
--- a/oml/tasks.py
+++ b/oml/tasks.py
@@ -29,6 +29,7 @@ class Tasks(Thread):
             if m:
                 try:
                     action, data = m
+                    logger.debug('run task %s', action)
                     if action == 'ping':
                         trigger_event('pong', data)
                     elif action == 'import':
@@ -47,6 +48,7 @@ class Tasks(Thread):
                         sync_metadata(*data)
                     else:
                         trigger_event('error', {'error': 'unknown action'})
+                    logger.debug('finished task %s', action)
                 except:
                     logger.debug('task failed', exc_info=1)
             self.q.task_done()