I'm trying to understand what this means. What exactly can get deleted as a result of assigning a no access to a user.
If you are not using Users list as a dimension in any of the modules then you can ignore this message.
What it means is that wherever you are using Users list as a dimension in any of the modules and your user had input the data, that data and all the dependent calculations for that user will be wiped out.
@Misbah Okay, I get it. Thanks for the good explanation.