diff --git a/Packages/cdms2/Lib/dataset.py b/Packages/cdms2/Lib/dataset.py
index 9fdd7004ae..cbc9548a0e 100644
--- a/Packages/cdms2/Lib/dataset.py
+++ b/Packages/cdms2/Lib/dataset.py
@@ -1258,7 +1258,7 @@ def copyAxis(self, axis, newname=None, unlimited=0, index=None, extbounds=None):
             if newaxis.isVirtual():
                 if len(axis)!=len(newaxis):
                     raise DuplicateAxisError(DuplicateAxis+newname)
-            elif unlimited==0 or (unlimited==1 and getNetcdfUseParallelFlag()==0):
+            elif unlimited==0 or (unlimited==1 and getNetcdfUseParallelFlag()!=0):
                 if len(axis)!=len(newaxis) or numpy.alltrue(numpy.less(numpy.absolute(newaxis[:]-axis[:]),1.e-5))==0:
                     raise DuplicateAxisError(DuplicateAxis+newname)
             else: