diff --git a/src/backend/models/filters.py b/src/backend/models/filters.py
index 0c9a2439..4cb519e3 100644
--- a/src/backend/models/filters.py
+++ b/src/backend/models/filters.py
@@ -33,42 +33,47 @@ class ModelFilter(ModelProxy):
         value: "ModelItem",
         _changed_fields: Optional[Dict[str, Any]] = None,
     ) -> None:
-        if self.accept_source(source):
-            value = self.convert_item(value)
+        with self.write_lock:
+            if self.accept_source(source):
+                value = self.convert_item(value)
 
-            if self.accept_item(value):
-                self.__setitem__((source.sync_id, key), value, _changed_fields)
-                self.filtered_out.pop((source.sync_id, key), None)
-            else:
-                self.filtered_out[source.sync_id, key] = value
-                self.pop((source.sync_id, key), None)
+                if self.accept_item(value):
+                    self.__setitem__(
+                        (source.sync_id, key), value, _changed_fields,
+                    )
+                    self.filtered_out.pop((source.sync_id, key), None)
+                else:
+                    self.filtered_out[source.sync_id, key] = value
+                    self.pop((source.sync_id, key), None)
 
-            for callback in self.items_changed_callbacks:
-                callback()
+                for callback in self.items_changed_callbacks:
+                    callback()
 
 
     def source_item_deleted(self, source: Model, key) -> None:
-        if self.accept_source(source):
-            try:
-                del self[source.sync_id, key]
-            except KeyError:
-                del self.filtered_out[source.sync_id, key]
+        with self.write_lock:
+            if self.accept_source(source):
+                try:
+                    del self[source.sync_id, key]
+                except KeyError:
+                    del self.filtered_out[source.sync_id, key]
 
-            for callback in self.items_changed_callbacks:
-                callback()
+                for callback in self.items_changed_callbacks:
+                    callback()
 
 
     def source_cleared(self, source: Model) -> None:
-        if self.accept_source(source):
-            for source_sync_id, key in self.copy():
-                if source_sync_id == source.sync_id:
-                    try:
-                        del self[source.sync_id, key]
-                    except KeyError:
-                        del self.filtered_out[source.sync_id, key]
+        with self.write_lock:
+            if self.accept_source(source):
+                for source_sync_id, key in self.copy():
+                    if source_sync_id == source.sync_id:
+                        try:
+                            del self[source.sync_id, key]
+                        except KeyError:
+                            del self.filtered_out[source.sync_id, key]
 
-            for callback in self.items_changed_callbacks:
-                callback()
+                for callback in self.items_changed_callbacks:
+                    callback()
 
 
     def refilter(
diff --git a/src/backend/models/model.py b/src/backend/models/model.py
index adbd4a29..3ba20d63 100644
--- a/src/backend/models/model.py
+++ b/src/backend/models/model.py
@@ -188,27 +188,28 @@ class Model(MutableMapping):
         and one `ModelItemDeleted` pyotherside event is fired per sequence.
         """
 
-        try:
-            self._active_batch_remove_indice = []
-            yield None
-        finally:
-            indice = self._active_batch_remove_indice
-            groups = [list(group) for item, group in itertools.groupby(indice)]
-            last   = None
+        with self.write_lock:
+            try:
+                self._active_batch_remove_indice = []
+                yield None
+            finally:
+                indice = self._active_batch_remove_indice
+                groups = [list(group) for item, group in itertools.groupby(indice)]
+                last   = None
 
-            if groups:
-                last = groups[-1].pop()
-                if not groups[-1]:
-                    del groups[-1]
+                if groups:
+                    last = groups[-1].pop()
+                    if not groups[-1]:
+                        del groups[-1]
 
-            for grp in groups:
-                ModelItemDeleted(self.sync_id, index=grp[0], count=len(grp))
+                for grp in groups:
+                    ModelItemDeleted(self.sync_id, index=grp[0], count=len(grp))
 
-            # Seems QML ListView has an horrible bug where removing a large
-            # amount of items at once will result in a corrupted empty display,
-            # this dumb workaround is the only way I've found
-            if last:
-                time.sleep(0.2)
-                ModelItemDeleted(self.sync_id, index=last, count=1)
+                # Seems QML ListView has an horrible bug where removing a large
+                # amount of items at once will result in a corrupted empty display,
+                # this dumb workaround is the only way I've found
+                if last:
+                    time.sleep(0.2)
+                    ModelItemDeleted(self.sync_id, index=last, count=1)
 
-            self._active_batch_remove_indice = None
+                self._active_batch_remove_indice = None
diff --git a/src/backend/models/proxy.py b/src/backend/models/proxy.py
index 8bbfab9a..5a8df83e 100644
--- a/src/backend/models/proxy.py
+++ b/src/backend/models/proxy.py
@@ -17,10 +17,11 @@ class ModelProxy(Model):
         self.take_items_ownership = False
         Model.proxies[sync_id] = self
 
-        for sync_id, model in Model.instances.items():
-            if sync_id != self.sync_id and self.accept_source(model):
-                for key, item in model.items():
-                    self.source_item_set(model, key, item)
+        with self.write_lock:
+            for sync_id, model in Model.instances.items():
+                if sync_id != self.sync_id and self.accept_source(model):
+                    for key, item in model.items():
+                        self.source_item_set(model, key, item)
 
 
     def accept_source(self, source: Model) -> bool: