diff --git a/fsl/wrappers/wrapperutils.py b/fsl/wrappers/wrapperutils.py
index 21829c13d1ae3035276ccbc69c899b47c31f5a1d..6728a23272696f295227291d723101cd366e7be5 100644
--- a/fsl/wrappers/wrapperutils.py
+++ b/fsl/wrappers/wrapperutils.py
@@ -915,7 +915,7 @@ def fileOrImage(*args, **kwargs):
 
         # create an independent in-memory
         # copy of the image file
-        img = nib.load(path)
+        img = nib.load(path, mmap=False)
 
         # if any arguments were fsl images,
         # that takes precedence.