diff --git a/IPython/utils/_process_win32.py b/IPython/utils/_process_win32.py
index 9b1ee5a..cf53c57 100644
--- a/IPython/utils/_process_win32.py
+++ b/IPython/utils/_process_win32.py
@@ -154,7 +154,7 @@ def getoutput(cmd):
         out = process_handler(cmd, lambda p: p.communicate()[0], STDOUT)
 
     if out is None:
-        out = ''
+        out = b''
     return py3compat.bytes_to_str(out)
 
 try: