diff --git a/apps/converter/backends/python/base.py b/apps/converter/backends/python/base.py
index 3e0f8cd84f..a57e1f0d2a 100644
--- a/apps/converter/backends/python/base.py
+++ b/apps/converter/backends/python/base.py
@@ -25,7 +25,7 @@ class ConverterClass(ConverterBase):
     def get_page_count(self, input_filepath):
         page_count = 1
 
-        mimetype, encoding = get_mimetype(input_filepath)
+        mimetype, encoding = get_mimetype(open(input_filepath, 'rb'), input_filepath)
         if mimetype == 'application/pdf':
             # If file is a PDF open it with slate to determine the page
             # count
@@ -50,7 +50,7 @@ class ConverterClass(ConverterBase):
 
     def convert_file(self, input_filepath, output_filepath, transformations=None, page=DEFAULT_PAGE_NUMBER, file_format=DEFAULT_FILE_FORMAT):
         tmpfile = None
-        mimetype, encoding = get_mimetype(input_filepath)
+        mimetype, encoding = get_mimetype(open(input_filepath, 'rb'), input_filepath)
         if mimetype == 'application/pdf' and USE_GHOSTSCRIPT:
             # If file is a PDF open it with ghostscript and convert it to
             # TIFF
diff --git a/apps/documents/models.py b/apps/documents/models.py
index 1d4b67881f..efdd6a6841 100644
--- a/apps/documents/models.py
+++ b/apps/documents/models.py
@@ -17,7 +17,7 @@ from converter.api import get_page_count
 from converter.api import get_available_transformations_choices
 from converter.api import convert
 from converter.exceptions import UnknownFileFormat, UnkownConvertError
-from mimetype.api import get_document_mimetype, get_icon_file_path, \
+from mimetype.api import get_mimetype, get_icon_file_path, \
     get_error_icon_file_path
 
 from documents.conf.settings import CHECKSUM_FUNCTION
@@ -135,7 +135,7 @@ class Document(models.Model):
         """
         if self.exists():
             try:
-                self.file_mimetype, self.mime_encoding = get_document_mimetype(self)
+                self.file_mimetype, self.mime_encoding = get_mimetype(self.open(), self.get_fullname())
             except:
                 self.file_mimetype = u''
                 self.file_mime_encoding = u''
diff --git a/apps/sources/staging.py b/apps/sources/staging.py
index 8a0a200859..b2edd41848 100644
--- a/apps/sources/staging.py
+++ b/apps/sources/staging.py
@@ -138,6 +138,7 @@ class StagingFile(object):
         try:
             return convert(self.filepath, size=size, cleanup_files=False, transformations=transformations)
         except UnknownFileFormat:
-            return get_icon_file_path(get_mimetype(self.filepath))
+            mimetype, encoding = get_mimetype(open(self.filepath, 'rb'), self.filepath)
+            return get_icon_file_path(mimetype)
         except UnkownConvertError:
             return get_error_icon_file_path()