I am having the issue in recently installed instance of Sage EM version 12 - "Alert cannot read property '$uuid' of undefined"
I get this error when I try to login to an End Point using some user Ids that have been created.
How can we resolve the issue
I would suggest taking a look at the user configuration setup for those users having the problem; under the administration module.
You may want to also review our KBID 69437 from our knowledgebase.
_uuid is a unique identifier used by MongoDB to identify a record within a collection within the database. you may have a missing _uuid for that user. It could be within the user setup itself, group setup, and/or role setup.