I'm running into a SQL Server SSIS problem, so I needed to run a program as a plain jane user. So I created a new user and by default they were added to the "Users" group.. So far so good.
I then tried to login as this user and received the "The local security policy does not allow you to login interactively".
So I logged back in as the local administrator and checked the Local Policies / User Rights Assignment / Log on locally. And sure enough, my new test user was not there... BUT... The entire box is grey'd out and I can't add or delete any user or group. I've tested this 3 or 4 times and rebooted, logged in/logged out etc. Log On as a service is unavailable for changes also.