diff --git a/easy_thumbnails/files.py b/easy_thumbnails/files.py
index <HASH>..<HASH> 100644
--- a/easy_thumbnails/files.py
+++ b/easy_thumbnails/files.py
@@ -176,7 +176,7 @@ class ThumbnailFile(ImageFieldFile):
         return self._file
 
     def _set_file(self, value):
-        if not isinstance(value, File):
+        if value is None and not isinstance(value, File):
             value = File(value)
         self._file = value
         self._committed = False
If ThumbnailFile.file is set to None, don't try to wrap it in a File class. Fixes #<I>