diff --git a/lib/galaxy/model/__init__.py b/lib/galaxy/model/__init__.py
index 667915d28de..8d735c7b3cd 100644
--- a/lib/galaxy/model/__init__.py
+++ b/lib/galaxy/model/__init__.py
@@ -50,9 +50,7 @@ from galaxy.web.form_builder import (AddressField, CheckboxField, HistoryField,
 
 log = logging.getLogger( __name__ )
 
-_datatypes_registry = galaxy.datatypes.registry.Registry()
-# Default Value Required for unit tests
-_datatypes_registry.load_datatypes()
+_datatypes_registry = None
 
 # When constructing filters with in for a fixed set of ids, maximum
 # number of items to place in the IN statement. Different databases
@@ -80,6 +78,12 @@ class ConverterDependencyException(Exception):
         return repr(self.value)
 
 
+def _get_datatypes_registry():
+    if _datatypes_registry is None:
+        raise Exception("galaxy.model.set_datatypes_registry must be called before performing certain DatasetInstance operations.")
+    return _datatypes_registry
+
+
 def set_datatypes_registry( d_registry ):
     """
     Set up datatypes_registry
@@ -1858,7 +1862,7 @@ class DatasetInstance( object ):
 
     @property
     def datatype( self ):
-        return _datatypes_registry.get_datatype_by_extension( self.extension )
+        return _get_datatypes_registry().get_datatype_by_extension( self.extension )
 
     def get_metadata( self ):
         # using weakref to store parent (to prevent circ ref),
@@ -1892,7 +1896,7 @@ class DatasetInstance( object ):
 
     def change_datatype( self, new_ext ):
         self.clear_associated_files()
-        _datatypes_registry.change_datatype( self, new_ext )
+        _get_datatypes_registry().change_datatype( self, new_ext )
 
     def get_size( self, nice_size=False ):
         """Returns the size of the data on disk"""
@@ -1929,7 +1933,7 @@ class DatasetInstance( object ):
     def get_mime( self ):
         """Returns the mime type of the data"""
         try:
-            return _datatypes_registry.get_mimetype_by_extension( self.extension.lower() )
+            return _get_datatypes_registry().get_mimetype_by_extension( self.extension.lower() )
         except AttributeError:
             # extension is None
             return 'data'
@@ -2054,14 +2058,14 @@ class DatasetInstance( object ):
         return None
 
     def get_converter_types(self):
-        return self.datatype.get_converter_types( self, _datatypes_registry )
+        return self.datatype.get_converter_types( self, _get_datatypes_registry() )
 
     def can_convert_to(self, format):
         return format in self.get_converter_types()
 
     def find_conversion_destination( self, accepted_formats, **kwd ):
         """Returns ( target_ext, existing converted dataset )"""
-        return self.datatype.find_conversion_destination( self, accepted_formats, _datatypes_registry, **kwd )
+        return self.datatype.find_conversion_destination( self, accepted_formats, _get_datatypes_registry(), **kwd )
 
     def add_validation_error( self, validation_error ):
         self.validation_errors.append( validation_error )
diff --git a/test/unit/tools/test_column_parameters.py b/test/unit/tools/test_column_parameters.py
index 44312dd1226..ac2cd968fe0 100644
--- a/test/unit/tools/test_column_parameters.py
+++ b/test/unit/tools/test_column_parameters.py
@@ -5,6 +5,7 @@ test_select_parameters.py.
 from galaxy.util import bunch
 from galaxy import model
 from .test_parameter_parsing import BaseParameterTestCase
+from tools_support import datatypes_registry
 
 
 class DataColumnParameterTestCase( BaseParameterTestCase ):
@@ -99,6 +100,6 @@ class DataColumnParameterTestCase( BaseParameterTestCase ):
             template_xml = '''<param name="my_name" type="%s" %s %s %s %s></param>'''
             param_str = template_xml % ( self.type, data_ref_text, multi_text, optional_text, self.other_attributes )
             self._param = self._parameter_for( xml=param_str )
-            self._param.ref_input = bunch.Bunch(formats=[model.datatypes_registry.get_datatype_by_extension("tabular")])
+            self._param.ref_input = bunch.Bunch(formats=[datatypes_registry.get_datatype_by_extension("tabular")])
 
         return self._param
diff --git a/test/unit/tools_support.py b/test/unit/tools_support.py
index 0249cb2bf88..0f78f857178 100644
--- a/test/unit/tools_support.py
+++ b/test/unit/tools_support.py
@@ -18,6 +18,11 @@ from galaxy.util.dbkeys import GenomeBuilds
 from galaxy.jobs import NoopQueue
 from galaxy.tools.parser import get_tool_source
 from galaxy.tools.deps.containers import NullContainerFinder
+import galaxy.datatypes.registry
+
+datatypes_registry = galaxy.datatypes.registry.Registry()
+datatypes_registry.load_datatypes()
+galaxy.model.set_datatypes_registry(datatypes_registry)
 
 
 class UsesApp( object ):