diff --git a/edbob/win32.py b/edbob/win32.py
index e74e650..96a76bd 100644
--- a/edbob/win32.py
+++ b/edbob/win32.py
@@ -163,6 +163,20 @@ def RegDeleteTree(key, subkey):
             pass
 
 
+def capture_output(command):
+    """
+    Runs ``command`` and returns any output it produces.
+    """
+
+    # We *need* to pipe ``stdout`` because that's how we capture the output of
+    # the ``hg`` command.  However, we must pipe *all* handles in order to
+    # prevent issues when running as a GUI but *from* the Windows console.
+    # See also: http://bugs.python.org/issue3905
+    kwargs = dict(stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    output = subprocess.Popen(command, **kwargs).communicate()[0]
+    return output
+
+
 def delayed_auto_start_service(name):
     """
     Configures the Windows service named ``name`` such that its startup type is