diff --git a/autoload/vebugger/lldb_wrapper.py b/autoload/vebugger/lldb_wrapper.py
index 534eb9e..cd6690c 100755
--- a/autoload/vebugger/lldb_wrapper.py
+++ b/autoload/vebugger/lldb_wrapper.py
@@ -213,6 +213,8 @@ class Debugger(object):
 
 
 def prefix_output(output, prefix):
+    if output is None:
+        output = ''
     lines = output.split('\n')
     lines = [prefix + line for line in lines]
     prefixed_output = '\n'.join(lines)