diff --git a/wcs/ctl/check_hobos.py b/wcs/ctl/check_hobos.py
index 5dab3e615..8cef45a15 100644
--- a/wcs/ctl/check_hobos.py
+++ b/wcs/ctl/check_hobos.py
@@ -434,6 +434,8 @@ class CmdCheckHobos(Command):
                 config.add_section('variables')
             for key, value in variables.items():
                 key = force_str(key)
+                if not isinstance(value, six.string_types):
+                    value = str(value)
                 value = force_str(value)
                 config.set('variables', key, value)