With OG set up, I go to admin/config/development/generate/user to generate some dummy users.
The process crashes with this error:
Error message EntityMalformedException: Missing bundle property on entity of type node. in entity_extract_ids() (line 7694 of includes/common.inc).
Here's a trimmed summary of the backtrace:
This then calls og_group(), and the problem seems to be that the $gid parameter is a group node type, rather than as the docs say:
* @param $gid * The group entity or ID.