diff --git a/beets/util/__init__.py b/beets/util/__init__.py
index 428de312a..bc07460e8 100644
--- a/beets/util/__init__.py
+++ b/beets/util/__init__.py
@@ -633,13 +633,14 @@ def command_output(cmd, shell=False):
     Python 2.6 and which can have problems if lots of output is sent to
     stderr.
     """
-    with open(os.devnull, 'wb') as devnull:
-        proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=devnull,
-                                close_fds=platform.system() != 'Windows',
-                                shell=shell)
-        stdout, _ = proc.communicate()
+    proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, 
+                            stderr=subprocess.PIPE,
+                            close_fds=platform.system() != 'Windows',
+                            shell=shell)
+    stdout, stderr  = proc.communicate()
+
     if proc.returncode:
-        raise subprocess.CalledProcessError(proc.returncode, cmd)
+        raise subprocess.CalledProcessError(proc.returncode, cmd, stderr)
     return stdout