diff --git a/blenderkit/__init__.py b/blenderkit/__init__.py
index d22f383b7a8abff7efeabb24e27a51a3f12f0831..9c9e07805d8e466b0ac76e0b1afcf8b296b2572b 100644
--- a/blenderkit/__init__.py
+++ b/blenderkit/__init__.py
@@ -151,15 +151,16 @@ def scene_load(context):
 @bpy.app.handlers.persistent
 def check_timers_timer():
     ''' checks if all timers are registered regularly. Prevents possible bugs from stopping the addon.'''
-    if not bpy.app.timers.is_registered(search.search_timer):
-        bpy.app.timers.register(search.search_timer)
-    if not bpy.app.timers.is_registered(download.download_timer):
-        bpy.app.timers.register(download.download_timer)
-    if not (bpy.app.timers.is_registered(tasks_queue.queue_worker)):
-        bpy.app.timers.register(tasks_queue.queue_worker)
-    if not bpy.app.timers.is_registered(bg_blender.bg_update):
-        bpy.app.timers.register(bg_blender.bg_update)
-    return 5.0
+    if not bpy.app.background:
+        if not bpy.app.timers.is_registered(search.search_timer):
+            bpy.app.timers.register(search.search_timer)
+        if not bpy.app.timers.is_registered(download.download_timer):
+            bpy.app.timers.register(download.download_timer)
+        if not (bpy.app.timers.is_registered(tasks_queue.queue_worker)):
+            bpy.app.timers.register(tasks_queue.queue_worker)
+        if not bpy.app.timers.is_registered(bg_blender.bg_update):
+            bpy.app.timers.register(bg_blender.bg_update)
+        return 5.0
 
 
 conditions = (
@@ -1907,7 +1908,7 @@ def register():
     asset_bar_op.register()
 
     user_preferences = bpy.context.preferences.addons['blenderkit'].preferences
-    if user_preferences.use_timers:
+    if user_preferences.use_timers and not bpy.app.background:
         bpy.app.timers.register(check_timers_timer, persistent=True)
 
     bpy.app.handlers.load_post.append(scene_load)
diff --git a/blenderkit/append_link.py b/blenderkit/append_link.py
index 56d37d540d81afe31059f5204d9fb0ab4f4af245..21cf2ec2b064e8bcff391b7fdb317d9afc86514c 100644
--- a/blenderkit/append_link.py
+++ b/blenderkit/append_link.py
@@ -330,6 +330,7 @@ def append_objects(file_name, obnames=[], location=(0, 0, 0), link=False, **kwar
             main_object.parent = bpy.data.objects[kwargs['parent']]
             main_object.matrix_world.translation = location
 
+
         #move objects that should be hidden to a sub collection
         if len(to_hidden_collection)>0 and collection is not None:
             hidden_collection_name = collection_name+'_hidden'
@@ -342,8 +343,11 @@ def append_objects(file_name, obnames=[], location=(0, 0, 0), link=False, **kwar
 
         bpy.ops.object.select_all(action='DESELECT')
         utils.selection_set(sel)
+        #let collection also store info that it was created by BlenderKit, for purging reasons
+        collection['is_blenderkit_asset'] = True
 
         return main_object, return_obs
+
     #this is used for uploads:
     with bpy.data.libraries.load(file_name, link=link, relative=True) as (data_from, data_to):
         sobs = []
diff --git a/blenderkit/bg_blender.py b/blenderkit/bg_blender.py
index c4294b304c9f00f500192d2427b7d4aa8cc8f78c..8fa0491f23aeb268a719b957b9f881b3f51f62e7 100644
--- a/blenderkit/bg_blender.py
+++ b/blenderkit/bg_blender.py
@@ -268,7 +268,7 @@ def add_bg_process(location=None, name=None, eval_path_computing='', eval_path_s
 def register():
     bpy.utils.register_class(KillBgProcess)
     user_preferences = bpy.context.preferences.addons['blenderkit'].preferences
-    if user_preferences.use_timers:
+    if user_preferences.use_timers and not bpy.app.background:
         bpy.app.timers.register(bg_update)
 
 
diff --git a/blenderkit/download.py b/blenderkit/download.py
index 2d5343b35ecb03d7170d7666e3200244b8007b6c..e6f886348730c61522f60aa83632e21c89515f7a 100644
--- a/blenderkit/download.py
+++ b/blenderkit/download.py
@@ -75,6 +75,10 @@ def check_missing():
 def check_unused():
     '''find assets that have been deleted from scene but their library is still present.'''
     # this is obviously broken. Blender should take care of the extra data automaticlaly
+    #first clean up collections
+    for c in bpy.data.collections:
+        if len(c.all_objects) == 0 and c.get('is_blenderkit_asset'):
+            bpy.data.collections.remove(c)
     return;
     used_libs = []
     for ob in bpy.data.objects:
@@ -493,6 +497,9 @@ def append_asset(asset_data, **kwargs):  # downloaders=[], location=None,
     asset_main['asset_data'] = asset_data  # TODO remove this??? should write to blenderkit Props?
     asset_main.blenderkit.asset_base_id = asset_data['assetBaseId']
     asset_main.blenderkit.id = asset_data['id']
+
+
+
     bpy.ops.wm.undo_push_context(message='add %s to scene' % asset_data['name'])
     # moving reporting to on save.
     # report_use_success(asset_data['id'])
@@ -1446,7 +1453,7 @@ def register_download():
     bpy.app.handlers.load_post.append(scene_load)
     bpy.app.handlers.save_pre.append(scene_save)
     user_preferences = bpy.context.preferences.addons['blenderkit'].preferences
-    if user_preferences.use_timers:
+    if user_preferences.use_timers and not bpy.app.background:
         bpy.app.timers.register(download_timer)
 
 
diff --git a/blenderkit/resolutions.py b/blenderkit/resolutions.py
index e24127864c0a1d41289d2bfc3242af3039f30d72..645a306d2f628cdc01dd4d94f74420fee19c30c1 100644
--- a/blenderkit/resolutions.py
+++ b/blenderkit/resolutions.py
@@ -171,10 +171,10 @@ def unpack_asset(data):
     #mark asset browser asset
     data_block = None
     if asset_data['assetType'] == 'model':
-        for ob in bpy.context.scene.objects:
-            if ob.parent == None:
-                ob.asset_mark()
-                data_block = ob
+        for c in bpy.data.collections:
+            if c.get('asset_data') is not None:
+                c.asset_mark()
+                data_block = c
     elif asset_data['assetType'] == 'material':
         for m in bpy.data.materials:
             m.asset_mark()
@@ -192,7 +192,8 @@ def unpack_asset(data):
             tags.remove(t)
         tags.new('description: ' + asset_data['description'])
         tags.new('tags: ' + ','.join(asset_data['tags']))
-        
+    #
+
     bpy.ops.wm.save_mainfile(compress=False)
     # now try to delete the .blend1 file
     try:
diff --git a/blenderkit/search.py b/blenderkit/search.py
index e846e8bcf268e56b9588967bb533c17a59c39996..50c3c480f7608e67ec5ea63e35717e7eb65bb67c 100644
--- a/blenderkit/search.py
+++ b/blenderkit/search.py
@@ -179,7 +179,7 @@ def scene_load(context):
     purge_search_results()
     fetch_server_data()
     categories.load_categories()
-    if not bpy.app.timers.is_registered(refresh_token_timer):
+    if not bpy.app.timers.is_registered(refresh_token_timer) and not bpy.app.background:
         bpy.app.timers.register(refresh_token_timer, persistent=True, first_interval=36000)
     update_assets_data()
 
@@ -1625,7 +1625,7 @@ def register_search():
         bpy.utils.register_class(c)
 
     user_preferences = bpy.context.preferences.addons['blenderkit'].preferences
-    if user_preferences.use_timers:
+    if user_preferences.use_timers and not bpy.app.background:
         bpy.app.timers.register(search_timer)
 
     categories.load_categories()
diff --git a/blenderkit/tasks_queue.py b/blenderkit/tasks_queue.py
index 0d9918788c6e208c57b3448c78622c9bc64a7349..248e9be780ffae3d66a5b1bbd110741134909396 100644
--- a/blenderkit/tasks_queue.py
+++ b/blenderkit/tasks_queue.py
@@ -29,7 +29,7 @@ bk_logger = logging.getLogger('blenderkit')
 @persistent
 def scene_load(context):
     user_preferences = bpy.context.preferences.addons['blenderkit'].preferences
-    if user_preferences.use_timers:
+    if user_preferences.use_timers and not bpy.app.background:
         if not (bpy.app.timers.is_registered(queue_worker)):
             bpy.app.timers.register(queue_worker)