Salesforce has resolved the access incident from 5/17. A subset of customers may still be experiencing issues with user permissions in SFDC and their teams continue to work on this. If you continue to experience issues, please see instructions for admins in the Known Issue article: http://sfdc.co/PermSetKI
. They will continue to make updates to this article. If your issues persist and cannot be resolved by the information in the Known Issue article, please log a case with SFDC Support.